def readinto(self, buff):
        """
        Read up to ``len(buff)`` bytes into ``bytearray`` *buff* and return the
        number of bytes read.

        :returns:
            The number of bytes read.
        """
        data = self.read(len(buff))
        buff[: len(data)] = data
        return len(data)
Read up to ``len(buff)`` bytes into ``bytearray`` *buff* and return the
        number of bytes read.

        :returns:
            The number of bytes read.