private async ValueTask ReadFrameAsync(CancellationToken cancellationToken)
{
await InnerTransport.ReadAllAsync(HeaderBuf, 0, HeaderSize, cancellationToken);
var size = DecodeFrameSize(HeaderBuf);
ReadBuffer.SetLength(size);
ReadBuffer.Seek(0, SeekOrigin.Begin);
ArraySegment <byte> bufSegment;
ReadBuffer.TryGetBuffer(out bufSegment);
await InnerTransport.ReadAllAsync(bufSegment.Array, 0, size, cancellationToken);
}