'Read up to sz bytes from the decompressed bytes buffer, and
read from the underlying transport if the decompression
buffer is empty.'

def read(self, sz):

    ret = self.__rbuf.read(sz)
    if (len(ret) > 0):
        return ret
    while True:
        if self.readComp(sz):
            break
    ret = self.__rbuf.read(sz)
    return ret
