add accessor for StreamId u32 (#639)

src/share.rs

@@ -108,9 +108,15 @@ pub struct SendStream<B> {
 /// new stream.
 ///
 /// [Section 5.1.1]: https://tools.ietf.org/html/rfc7540#section-5.1.1
-#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
 pub struct StreamId(u32);
 
+impl From<StreamId> for u32 {
+    fn from(src: StreamId) -> Self {
+        src.0
+    }
+}
+
 /// Receives the body stream and trailers from the remote peer.
 ///
 /// A `RecvStream` is provided by [`client::ResponseFuture`] and
@@ -382,6 +388,18 @@ impl StreamId {
     pub(crate) fn from_internal(id: crate::frame::StreamId) -> Self {
         StreamId(id.into())
     }
+
+    /// Returns the `u32` corresponding to this `StreamId`
+    ///
+    /// # Note
+    ///
+    /// This is the same as the `From<StreamId>` implementation, but
+    /// included as an inherent method because that implementation doesn't
+    /// appear in rustdocs, as well as a way to force the type instead of
+    /// relying on inference.
+    pub fn as_u32(&self) -> u32 {
+        (*self).into()
+    }
 }
 // ===== impl RecvStream =====