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    use std::u32;

    /// A stream identifier, as described in [Section 5.1.1] of RFC 7540.
    ///
    /// Streams are identified with an unsigned 31-bit integer. Streams
    /// initiated by a client MUST use odd-numbered stream identifiers; those
    /// initiated by the server MUST use even-numbered stream identifiers.  A
    /// stream identifier of zero (0x0) is used for connection control
    /// messages; the stream identifier of zero cannot be used to establish a
    /// new stream.
    ///
    /// [Section 5.1.1]: https://tools.ietf.org/html/rfc7540#section-5.1.1
    #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
    pub struct StreamId(u32);

    #[derive(Debug, Copy, Clone)]
    pub struct StreamIdOverflow;

    const STREAM_ID_MASK: u32 = 1 << 31;

    impl StreamId {
        /// Stream ID 0.
        pub const ZERO: StreamId = StreamId(0);

        /// The maximum allowed stream ID.
        pub const MAX: StreamId = StreamId(u32::MAX >> 1);

        /// Parse the stream ID
        #[inline]
        pub fn parse(buf: &[u8]) -> (StreamId, bool) {
            let mut ubuf = [0; 4];
            ubuf.copy_from_slice(&buf[0..4]);
            let unpacked = u32::from_be_bytes(ubuf);
            let flag = unpacked & STREAM_ID_MASK == STREAM_ID_MASK;

            // Now clear the most significant bit, as that is reserved and MUST be
            // ignored when received.
            (StreamId(unpacked & !STREAM_ID_MASK), flag)
        }

        /// Returns true if this stream ID corresponds to a stream that
        /// was initiated by the client.
        pub fn is_client_initiated(&self) -> bool {
            let id = self.0;
            id != 0 && id % 2 == 1
        }

        /// Returns true if this stream ID corresponds to a stream that
        /// was initiated by the server.
        pub fn is_server_initiated(&self) -> bool {
            let id = self.0;
            id != 0 && id % 2 == 0
        }

        /// Return a new `StreamId` for stream 0.
        #[inline]
        pub fn zero() -> StreamId {
            StreamId::ZERO
        }

        /// Returns true if this stream ID is zero.
        pub fn is_zero(&self) -> bool {
            self.0 == 0
        }

        /// Returns the next stream ID initiated by the same peer as this stream
        /// ID, or an error if incrementing this stream ID would overflow the
        /// maximum.
        pub fn next_id(&self) -> Result<StreamId, StreamIdOverflow> {
            let next = self.0 + 2;
            if next > StreamId::MAX.0 {
                Err(StreamIdOverflow)
            } else {
                Ok(StreamId(next))
            }
        }
    }

    impl From<u32> for StreamId {
        fn from(src: u32) -> Self {
            assert_eq!(src & STREAM_ID_MASK, 0, "invalid stream ID -- MSB is set");
            StreamId(src)
        }
    }

    impl From<StreamId> for u32 {
        fn from(src: StreamId) -> Self {
            src.0
        }
    }

    impl PartialEq<u32> for StreamId {
        fn eq(&self, other: &u32) -> bool {
            self.0 == *other
        }
    }