feat(frame): add reset API for frame codec

[PureWhiteWu]

In our previous usage, we are using it like this way:

pub fn decode(&self, mut data: Bytes) -> Result<Bytes> {
    self.detect(&mut data)?;
    let rd = data.reader();
    let mut rd: Box<dyn Read> = match self {
        CodecType::Gzip => Box::new(GzDecoder::new(rd)),
        CodecType::Snappy => Box::new(FrameDecoder::new(rd)),
        CodecType::Noop => Box::new(rd),
    };

    let mut buf = Vec::new();
    rd.read_to_end(&mut buf)?;
    Ok(buf.into())
}

And we found that there's a lot of memory allocation in the flamegraph which uses about 25% of cpu:

After I added the reset API and uses it like this way:

thread_local! {
    static SNAP_DECODER: RefCell<FrameDecoder<Reader<Bytes>>> = RefCell::new(FrameDecoder::new(Bytes::new().reader()));
    static MAX_SIZE: RefCell<usize> = RefCell::new(4096);
}

pub fn decode(&self, mut data: Bytes) -> Result<Vec<u8>> {
    self.detect(&mut data)?;
    let rd = data.reader();
    SNAP_DECODER.with(|s| {
        let mut snap_decoder = s.borrow_mut();
        let mut rd: Box<dyn Read> = match self {
            Self::Gzip => Box::new(GzDecoder::new(rd)),
            Self::Snappy => {
                snap_decoder.reset(rd);
                Box::new(&mut *snap_decoder)
            }
            Self::Noop => Box::new(rd),
        };

        MAX_SIZE.with(|s| {
            let mut size = s.borrow_mut();
            let mut buf = Vec::with_capacity(*size);
            rd.read_to_end(&mut buf)?;
            if buf.len() > *size {
                *size = buf.len();
            }
            Ok(buf)
        })
    })
}

The CPU usage of this part is greatly reduced and can even be ignored:

[PureWhiteWu]

r? @BurntSushi

[PureWhiteWu]

ping~ @BurntSushi

[PureWhiteWu]

Kindly remind if you missed this @BurntSushi