def prefetch_size(self, value, all_channels=False):
        if value is None:
            return
        self.rpc(spec.Basic.Qos(prefetch_size=value, global_=all_channels))
Set a prefetch size in bytes for the channel (or all channels on the
dataset/ETHPy150Open gmr/rabbitpy/rabbitpy/channel.py/Channel.prefetch_size