Merge #657

657: Async usb stack r=Dirbaio a=Dirbaio

TODO

- [x] Make it work on nRF
- [x] Add a way for classes to handle their own EP0 control requests - thanks `@alexmoon!`
- [x] Handle CONTROL OUT requests with data.
- [ ] Impl AsyncRead/AsyncWrite for CDC ACM -- will do later, it's not trivial
- [x] Cleanup unwraps/asserts/panics
- [x] Cleanup logs (make everything trace/debug, not info)
- [ ] Port synopsys-usb-otg
- [ ] Port stm32-usbd
- [ ] Add more classes? HID, MSD?


Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>
Co-authored-by: alexmoon <alex.r.moon@gmail.com>

examples/nrf/Cargo.toml

@@ -1,16 +1,19 @@
 [package]
 authors = ["Dario Nieuwenhuis <dirbaio@dirbaio.net>"]
-edition = "2018"
+edition = "2021"
 name = "embassy-nrf-examples"
 version = "0.1.0"
 
 [features]
 default = ["nightly"]
-nightly = ["embassy-nrf/nightly", "embassy-nrf/unstable-traits"]
+nightly = ["embassy-nrf/nightly", "embassy-nrf/unstable-traits", "embassy-usb", "embassy-usb-serial", "embassy-usb-hid"]
 
 [dependencies]
 embassy = { version = "0.1.0", path = "../../embassy", features = ["defmt", "defmt-timestamp-uptime"] }
-embassy-nrf = { version = "0.1.0", path = "../../embassy-nrf", features = ["defmt", "nrf52840", "time-driver-rtc1", "gpiote"] }
+embassy-nrf = { version = "0.1.0", path = "../../embassy-nrf", features = ["defmt", "nrf52840", "time-driver-rtc1", "gpiote", "unstable-pac"] }
+embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt"], optional = true }
+embassy-usb-serial = { version = "0.1.0", path = "../../embassy-usb-serial", features = ["defmt"], optional = true }
+embassy-usb-hid = { version = "0.1.0", path = "../../embassy-usb-hid", features = ["defmt"], optional = true }
 
 defmt = "0.3"
 defmt-rtt = "0.3"
@@ -21,6 +24,5 @@ panic-probe = { version = "0.3", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 rand = { version = "0.8.4", default-features = false }
 embedded-storage = "0.3.0"
-
-usb-device = "0.2"
-usbd-serial = "0.1.1"
+usbd-hid = "0.5.2"
+serde = { version = "1.0.136", default-features = false }

examples/nrf/src/bin/usb_hid_keyboard.rs

@@ -0,0 +1,148 @@
+#![no_std]
+#![no_main]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+use core::mem;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::Duration;
+use embassy_nrf::gpio::{Input, Pin, Pull};
+use embassy_nrf::interrupt;
+use embassy_nrf::pac;
+use embassy_nrf::usb::Driver;
+use embassy_nrf::Peripherals;
+use embassy_usb::control::OutResponse;
+use embassy_usb::{Config, UsbDeviceBuilder};
+use embassy_usb_hid::{HidClass, ReportId, RequestHandler, State};
+use futures::future::join;
+use usbd_hid::descriptor::{KeyboardReport, SerializedDescriptor};
+
+use defmt_rtt as _; // global logger
+use panic_probe as _;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let clock: pac::CLOCK = unsafe { mem::transmute(()) };
+    let power: pac::POWER = unsafe { mem::transmute(()) };
+
+    info!("Enabling ext hfosc...");
+    clock.tasks_hfclkstart.write(|w| unsafe { w.bits(1) });
+    while clock.events_hfclkstarted.read().bits() != 1 {}
+
+    info!("Waiting for vbus...");
+    while !power.usbregstatus.read().vbusdetect().is_vbus_present() {}
+    info!("vbus OK");
+
+    // Create the driver, from the HAL.
+    let irq = interrupt::take!(USBD);
+    let driver = Driver::new(p.USBD, irq);
+
+    // Create embassy-usb Config
+    let mut config = Config::new(0xc0de, 0xcafe);
+    config.manufacturer = Some("Tactile Engineering");
+    config.product = Some("Testy");
+    config.serial_number = Some("12345678");
+    config.max_power = 100;
+    config.max_packet_size_0 = 64;
+
+    // Create embassy-usb DeviceBuilder using the driver and config.
+    // It needs some buffers for building the descriptors.
+    let mut device_descriptor = [0; 256];
+    let mut config_descriptor = [0; 256];
+    let mut bos_descriptor = [0; 256];
+    let mut control_buf = [0; 16];
+    let request_handler = MyRequestHandler {};
+
+    let mut state = State::<8, 1>::new();
+
+    let mut builder = UsbDeviceBuilder::new(
+        driver,
+        config,
+        &mut device_descriptor,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut control_buf,
+    );
+
+    // Create classes on the builder.
+    let hid = HidClass::with_output_ep(
+        &mut builder,
+        &mut state,
+        KeyboardReport::desc(),
+        Some(&request_handler),
+        60,
+        64,
+    );
+
+    // Build the builder.
+    let mut usb = builder.build().await;
+
+    // Run the USB device.
+    let usb_fut = usb.run();
+
+    let mut button = Input::new(p.P0_11.degrade(), Pull::Up);
+
+    let (mut hid_in, hid_out) = hid.split();
+
+    // Do stuff with the class!
+    let in_fut = async {
+        loop {
+            button.wait_for_low().await;
+            info!("PRESSED");
+            let report = KeyboardReport {
+                keycodes: [4, 0, 0, 0, 0, 0],
+                leds: 0,
+                modifier: 0,
+                reserved: 0,
+            };
+            match hid_in.serialize(&report).await {
+                Ok(()) => {}
+                Err(e) => warn!("Failed to send report: {:?}", e),
+            };
+
+            button.wait_for_high().await;
+            info!("RELEASED");
+            let report = KeyboardReport {
+                keycodes: [0, 0, 0, 0, 0, 0],
+                leds: 0,
+                modifier: 0,
+                reserved: 0,
+            };
+            match hid_in.serialize(&report).await {
+                Ok(()) => {}
+                Err(e) => warn!("Failed to send report: {:?}", e),
+            };
+        }
+    };
+
+    let out_fut = async {
+        hid_out.run(false, &request_handler).await;
+    };
+    // Run everything concurrently.
+    // If we had made everything `'static` above instead, we could do this using separate tasks instead.
+    join(usb_fut, join(in_fut, out_fut)).await;
+}
+
+struct MyRequestHandler {}
+
+impl RequestHandler for MyRequestHandler {
+    fn get_report(&self, id: ReportId, _buf: &mut [u8]) -> Option<usize> {
+        info!("Get report for {:?}", id);
+        None
+    }
+
+    fn set_report(&self, id: ReportId, data: &[u8]) -> OutResponse {
+        info!("Set report for {:?}: {=[u8]}", id, data);
+        OutResponse::Accepted
+    }
+
+    fn set_idle(&self, id: Option<ReportId>, dur: Duration) {
+        info!("Set idle rate for {:?} to {:?}", id, dur);
+    }
+
+    fn get_idle(&self, id: Option<ReportId>) -> Option<Duration> {
+        info!("Get idle rate for {:?}", id);
+        None
+    }
+}

examples/nrf/src/bin/usb_hid_mouse.rs

@@ -0,0 +1,129 @@
+#![no_std]
+#![no_main]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+use core::mem;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::interrupt;
+use embassy_nrf::pac;
+use embassy_nrf::usb::Driver;
+use embassy_nrf::Peripherals;
+use embassy_usb::control::OutResponse;
+use embassy_usb::{Config, UsbDeviceBuilder};
+use embassy_usb_hid::{HidClass, ReportId, RequestHandler, State};
+use futures::future::join;
+use usbd_hid::descriptor::{MouseReport, SerializedDescriptor};
+
+use defmt_rtt as _; // global logger
+use panic_probe as _;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let clock: pac::CLOCK = unsafe { mem::transmute(()) };
+    let power: pac::POWER = unsafe { mem::transmute(()) };
+
+    info!("Enabling ext hfosc...");
+    clock.tasks_hfclkstart.write(|w| unsafe { w.bits(1) });
+    while clock.events_hfclkstarted.read().bits() != 1 {}
+
+    info!("Waiting for vbus...");
+    while !power.usbregstatus.read().vbusdetect().is_vbus_present() {}
+    info!("vbus OK");
+
+    // Create the driver, from the HAL.
+    let irq = interrupt::take!(USBD);
+    let driver = Driver::new(p.USBD, irq);
+
+    // Create embassy-usb Config
+    let mut config = Config::new(0xc0de, 0xcafe);
+    config.manufacturer = Some("Tactile Engineering");
+    config.product = Some("Testy");
+    config.serial_number = Some("12345678");
+    config.max_power = 100;
+
+    // Create embassy-usb DeviceBuilder using the driver and config.
+    // It needs some buffers for building the descriptors.
+    let mut device_descriptor = [0; 256];
+    let mut config_descriptor = [0; 256];
+    let mut bos_descriptor = [0; 256];
+    let mut control_buf = [0; 16];
+    let request_handler = MyRequestHandler {};
+
+    let mut control = State::<5, 0>::new();
+
+    let mut builder = UsbDeviceBuilder::new(
+        driver,
+        config,
+        &mut device_descriptor,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut control_buf,
+    );
+
+    // Create classes on the builder.
+    let mut hid = HidClass::new(
+        &mut builder,
+        &mut control,
+        MouseReport::desc(),
+        Some(&request_handler),
+        60,
+        8,
+    );
+
+    // Build the builder.
+    let mut usb = builder.build().await;
+
+    // Run the USB device.
+    let usb_fut = usb.run();
+
+    // Do stuff with the class!
+    let hid_fut = async {
+        let mut y: i8 = 5;
+        loop {
+            Timer::after(Duration::from_millis(500)).await;
+
+            y = -y;
+            let report = MouseReport {
+                buttons: 0,
+                x: 0,
+                y,
+                wheel: 0,
+                pan: 0,
+            };
+            match hid.input().serialize(&report).await {
+                Ok(()) => {}
+                Err(e) => warn!("Failed to send report: {:?}", e),
+            }
+        }
+    };
+
+    // Run everything concurrently.
+    // If we had made everything `'static` above instead, we could do this using separate tasks instead.
+    join(usb_fut, hid_fut).await;
+}
+
+struct MyRequestHandler {}
+
+impl RequestHandler for MyRequestHandler {
+    fn get_report(&self, id: ReportId, _buf: &mut [u8]) -> Option<usize> {
+        info!("Get report for {:?}", id);
+        None
+    }
+
+    fn set_report(&self, id: ReportId, data: &[u8]) -> OutResponse {
+        info!("Set report for {:?}: {=[u8]}", id, data);
+        OutResponse::Accepted
+    }
+
+    fn set_idle(&self, id: Option<ReportId>, dur: Duration) {
+        info!("Set idle rate for {:?} to {:?}", id, dur);
+    }
+
+    fn get_idle(&self, id: Option<ReportId>) -> Option<Duration> {
+        info!("Get idle rate for {:?}", id);
+        None
+    }
+}

examples/nrf/src/bin/usb_serial.rs

@@ -0,0 +1,113 @@
+#![no_std]
+#![no_main]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+use core::mem;
+use defmt::{info, panic};
+use embassy::executor::Spawner;
+use embassy_nrf::interrupt;
+use embassy_nrf::pac;
+use embassy_nrf::usb::{Driver, Instance};
+use embassy_nrf::Peripherals;
+use embassy_usb::driver::{ReadError, WriteError};
+use embassy_usb::{Config, UsbDeviceBuilder};
+use embassy_usb_serial::{CdcAcmClass, State};
+use futures::future::join;
+
+use defmt_rtt as _; // global logger
+use panic_probe as _;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let clock: pac::CLOCK = unsafe { mem::transmute(()) };
+    let power: pac::POWER = unsafe { mem::transmute(()) };
+
+    info!("Enabling ext hfosc...");
+    clock.tasks_hfclkstart.write(|w| unsafe { w.bits(1) });
+    while clock.events_hfclkstarted.read().bits() != 1 {}
+
+    info!("Waiting for vbus...");
+    while !power.usbregstatus.read().vbusdetect().is_vbus_present() {}
+    info!("vbus OK");
+
+    // Create the driver, from the HAL.
+    let irq = interrupt::take!(USBD);
+    let driver = Driver::new(p.USBD, irq);
+
+    // Create embassy-usb Config
+    let config = Config::new(0xc0de, 0xcafe);
+
+    // Create embassy-usb DeviceBuilder using the driver and config.
+    // It needs some buffers for building the descriptors.
+    let mut device_descriptor = [0; 256];
+    let mut config_descriptor = [0; 256];
+    let mut bos_descriptor = [0; 256];
+    let mut control_buf = [0; 7];
+
+    let mut state = State::new();
+
+    let mut builder = UsbDeviceBuilder::new(
+        driver,
+        config,
+        &mut device_descriptor,
+        &mut config_descriptor,
+        &mut bos_descriptor,
+        &mut control_buf,
+    );
+
+    // Create classes on the builder.
+    let mut class = CdcAcmClass::new(&mut builder, &mut state, 64);
+
+    // Build the builder.
+    let mut usb = builder.build().await;
+
+    // Run the USB device.
+    let usb_fut = usb.run();
+
+    // Do stuff with the class!
+    let echo_fut = async {
+        loop {
+            class.wait_connection().await;
+            info!("Connected");
+            let _ = echo(&mut class).await;
+            info!("Disconnected");
+        }
+    };
+
+    // Run everything concurrently.
+    // If we had made everything `'static` above instead, we could do this using separate tasks instead.
+    join(usb_fut, echo_fut).await;
+}
+
+struct Disconnected {}
+
+impl From<ReadError> for Disconnected {
+    fn from(val: ReadError) -> Self {
+        match val {
+            ReadError::BufferOverflow => panic!("Buffer overflow"),
+            ReadError::Disabled => Disconnected {},
+        }
+    }
+}
+
+impl From<WriteError> for Disconnected {
+    fn from(val: WriteError) -> Self {
+        match val {
+            WriteError::BufferOverflow => panic!("Buffer overflow"),
+            WriteError::Disabled => Disconnected {},
+        }
+    }
+}
+
+async fn echo<'d, T: Instance + 'd>(
+    class: &mut CdcAcmClass<'d, Driver<'d, T>>,
+) -> Result<(), Disconnected> {
+    let mut buf = [0; 64];
+    loop {
+        let n = class.read_packet(&mut buf).await?;
+        let data = &buf[..n];
+        info!("data: {:x}", data);
+        class.write_packet(data).await?;
+    }
+}

examples/nrf/src/bin/usb_serial_multitask.rs

@@ -0,0 +1,122 @@
+#![no_std]
+#![no_main]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+use core::mem;
+use defmt::{info, panic, unwrap};
+use embassy::executor::Spawner;
+use embassy::util::Forever;
+use embassy_nrf::pac;
+use embassy_nrf::usb::Driver;
+use embassy_nrf::Peripherals;
+use embassy_nrf::{interrupt, peripherals};
+use embassy_usb::driver::{ReadError, WriteError};
+use embassy_usb::{Config, UsbDevice, UsbDeviceBuilder};
+use embassy_usb_serial::{CdcAcmClass, State};
+
+use defmt_rtt as _; // global logger
+use panic_probe as _;
+
+type MyDriver = Driver<'static, peripherals::USBD>;
+
+#[embassy::task]
+async fn usb_task(mut device: UsbDevice<'static, MyDriver>) {
+    device.run().await;
+}
+
+#[embassy::task]
+async fn echo_task(mut class: CdcAcmClass<'static, MyDriver>) {
+    loop {
+        class.wait_connection().await;
+        info!("Connected");
+        let _ = echo(&mut class).await;
+        info!("Disconnected");
+    }
+}
+
+#[embassy::main]
+async fn main(spawner: Spawner, p: Peripherals) {
+    let clock: pac::CLOCK = unsafe { mem::transmute(()) };
+    let power: pac::POWER = unsafe { mem::transmute(()) };
+
+    info!("Enabling ext hfosc...");
+    clock.tasks_hfclkstart.write(|w| unsafe { w.bits(1) });
+    while clock.events_hfclkstarted.read().bits() != 1 {}
+
+    info!("Waiting for vbus...");
+    while !power.usbregstatus.read().vbusdetect().is_vbus_present() {}
+    info!("vbus OK");
+
+    // Create the driver, from the HAL.
+    let irq = interrupt::take!(USBD);
+    let driver = Driver::new(p.USBD, irq);
+
+    // Create embassy-usb Config
+    let config = Config::new(0xc0de, 0xcafe);
+
+    struct Resources {
+        device_descriptor: [u8; 256],
+        config_descriptor: [u8; 256],
+        bos_descriptor: [u8; 256],
+        control_buf: [u8; 7],
+        serial_state: State<'static>,
+    }
+    static RESOURCES: Forever<Resources> = Forever::new();
+    let res = RESOURCES.put(Resources {
+        device_descriptor: [0; 256],
+        config_descriptor: [0; 256],
+        bos_descriptor: [0; 256],
+        control_buf: [0; 7],
+        serial_state: State::new(),
+    });
+
+    // Create embassy-usb DeviceBuilder using the driver and config.
+    let mut builder = UsbDeviceBuilder::new(
+        driver,
+        config,
+        &mut res.device_descriptor,
+        &mut res.config_descriptor,
+        &mut res.bos_descriptor,
+        &mut res.control_buf,
+    );
+
+    // Create classes on the builder.
+    let class = CdcAcmClass::new(&mut builder, &mut res.serial_state, 64);
+
+    // Build the builder.
+    let usb = builder.build().await;
+
+    unwrap!(spawner.spawn(usb_task(usb)));
+    unwrap!(spawner.spawn(echo_task(class)));
+}
+
+struct Disconnected {}
+
+impl From<ReadError> for Disconnected {
+    fn from(val: ReadError) -> Self {
+        match val {
+            ReadError::BufferOverflow => panic!("Buffer overflow"),
+            ReadError::Disabled => Disconnected {},
+        }
+    }
+}
+
+impl From<WriteError> for Disconnected {
+    fn from(val: WriteError) -> Self {
+        match val {
+            WriteError::BufferOverflow => panic!("Buffer overflow"),
+            WriteError::Disabled => Disconnected {},
+        }
+    }
+}
+
+async fn echo(class: &mut CdcAcmClass<'static, MyDriver>) -> Result<(), Disconnected> {
+    let mut buf = [0; 64];
+    loop {
+        let n = class.read_packet(&mut buf).await?;
+        let data = &buf[..n];
+        info!("data: {:x}", data);
+        class.write_packet(data).await?;
+    }
+}

examples/nrf/src/bin/usb_uart.rs

@@ -1,89 +0,0 @@
-#![no_std]
-#![no_main]
-#![feature(type_alias_impl_trait)]
-
-use defmt::{info, unwrap};
-use embassy::executor::Spawner;
-use embassy::interrupt::InterruptExt;
-use embassy::io::{AsyncBufReadExt, AsyncWriteExt};
-use embassy_nrf::usb::{State, Usb, UsbBus, UsbSerial};
-use embassy_nrf::{interrupt, Peripherals};
-use futures::pin_mut;
-use usb_device::device::{UsbDeviceBuilder, UsbVidPid};
-
-use defmt_rtt as _; // global logger
-use panic_probe as _; // print out panic messages
-
-#[embassy::main]
-async fn main(_spawner: Spawner, p: Peripherals) {
-    let mut rx_buffer = [0u8; 64];
-    // we send back input + cr + lf
-    let mut tx_buffer = [0u8; 66];
-
-    let usb_bus = UsbBus::new(p.USBD);
-
-    let serial = UsbSerial::new(&usb_bus, &mut rx_buffer, &mut tx_buffer);
-
-    let device = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
-        .manufacturer("Fake company")
-        .product("Serial port")
-        .serial_number("TEST")
-        .device_class(0x02)
-        .build();
-
-    let irq = interrupt::take!(USBD);
-    irq.set_priority(interrupt::Priority::P3);
-
-    let mut state = State::new();
-    let usb = unsafe { Usb::new(&mut state, device, serial, irq) };
-    pin_mut!(usb);
-
-    let (mut reader, mut writer) = usb.as_ref().take_serial_0();
-
-    info!("usb initialized!");
-
-    unwrap!(
-        writer
-            .write_all(b"\r\nInput returned upper cased on CR+LF\r\n")
-            .await
-    );
-
-    let mut buf = [0u8; 64];
-    loop {
-        let mut n = 0;
-
-        async {
-            loop {
-                let char = unwrap!(reader.read_byte().await);
-
-                // throw away, read more on cr, exit on lf
-                if char == b'\r' {
-                    continue;
-                } else if char == b'\n' {
-                    break;
-                }
-
-                buf[n] = char;
-                n += 1;
-
-                // stop if we're out of room
-                if n == buf.len() {
-                    break;
-                }
-            }
-        }
-        .await;
-
-        if n > 0 {
-            for char in buf[..n].iter_mut() {
-                // upper case
-                if 0x61 <= *char && *char <= 0x7a {
-                    *char &= !0x20;
-                }
-            }
-            unwrap!(writer.write_all(&buf[..n]).await);
-            unwrap!(writer.write_all(b"\r\n").await);
-            unwrap!(writer.flush().await);
-        }
-    }
-}

examples/nrf/src/bin/usb_uart_io.rs

@@ -1,66 +0,0 @@
-#![no_std]
-#![no_main]
-#![feature(type_alias_impl_trait)]
-
-use defmt::{info, unwrap};
-use embassy::executor::Spawner;
-use embassy::interrupt::InterruptExt;
-use embassy::io::{read_line, AsyncWriteExt};
-use embassy_nrf::usb::{State, Usb, UsbBus, UsbSerial};
-use embassy_nrf::{interrupt, Peripherals};
-use futures::pin_mut;
-use usb_device::device::{UsbDeviceBuilder, UsbVidPid};
-
-use defmt_rtt as _; // global logger
-use panic_probe as _; // print out panic messages
-
-#[embassy::main]
-async fn main(_spawner: Spawner, p: Peripherals) {
-    let mut rx_buffer = [0u8; 64];
-    // we send back input + cr + lf
-    let mut tx_buffer = [0u8; 66];
-
-    let usb_bus = UsbBus::new(p.USBD);
-
-    let serial = UsbSerial::new(&usb_bus, &mut rx_buffer, &mut tx_buffer);
-
-    let device = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
-        .manufacturer("Fake company")
-        .product("Serial port")
-        .serial_number("TEST")
-        .device_class(0x02)
-        .build();
-
-    let irq = interrupt::take!(USBD);
-    irq.set_priority(interrupt::Priority::P3);
-
-    let mut state = State::new();
-    let usb = unsafe { Usb::new(&mut state, device, serial, irq) };
-    pin_mut!(usb);
-
-    let (mut reader, mut writer) = usb.as_ref().take_serial_0();
-
-    info!("usb initialized!");
-
-    unwrap!(
-        writer
-            .write_all(b"\r\nInput returned upper cased on CR+LF\r\n")
-            .await
-    );
-
-    let mut buf = [0u8; 64];
-    loop {
-        let n = unwrap!(read_line(&mut reader, &mut buf).await);
-
-        for char in buf[..n].iter_mut() {
-            // upper case
-            if 0x61 <= *char && *char <= 0x7a {
-                *char &= !0x20;
-            }
-        }
-
-        unwrap!(writer.write_all(&buf[..n]).await);
-        unwrap!(writer.write_all(b"\r\n").await);
-        unwrap!(writer.flush().await);
-    }
-}