Convert between frames and higher-level AMQP methods
Helper class to receive frames from the broker, combine them if necessary with content-headers and content-bodies into complete methods.
Normally a method is represented as a tuple containing (channel, method_sig, args, content).
In the case of a framing error, an ConnectionError is placed in the queue.
In the case of unexpected frames, a tuple made up of (channel, ChannelError) is placed in the queue.
Read a method from the peer.