Chops the tail off the stream starting at 0 and ending at C{tell()}.
        The stream pointer is set to 0 at the end of this function.

        @since: 0.4

def consume(self):
        """
        Chops the tail off the stream starting at 0 and ending at C{tell()}.
        The stream pointer is set to 0 at the end of this function.

        @since: 0.4
        """
        try:
            bytes = self.read()
        except IOError:
            bytes = ''

        self.truncate()

        if len(bytes) > 0:
            self.write(bytes)
            self.seek(0)