Add a convenience next(range) to Rng.

embassy-traits/src/rng.rs

@@ -4,6 +4,7 @@ use core::future::Future;
 pub trait Rng {
     type Error;
 
+    #[rustfmt::skip]
     type RngFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a
     where
         Self: 'a;
@@ -14,4 +15,11 @@ pub trait Rng {
     /// filling the buffer. Upon completion, the buffer will be completely
     /// filled or an error will have been reported.
     fn fill_bytes<'a>(&'a mut self, dest: &'a mut [u8]) -> Self::RngFuture<'a>;
+
+    #[rustfmt::skip]
+    type NextFuture<'a>: Future<Output = Result<u32, Self::Error>> + 'a
+    where
+        Self: 'a;
+
+    fn next<'a>(&'a mut self, range: u32) -> Self::NextFuture<'a>;
 }