Function test_codec

pub fn test_codec<R: AsyncRead, W: AsyncWrite, D: AsyncDecode, C: AsyncEncode>(
    reader: R,
    writer: W,
    dec: D,
    co: C,
) -> (D::Item, bool)
where
    D::Error: Debug,

Run an encoder and a decoder concurrently, returning the decoded output and whether the encoder produced as many bytes as the decoder consumed.