def _parse_one_event(self):
        """Parse the stream buffer and return either a single event or None"""
        # WVA includes \r\n between messages which the parser doesn't like, so we
        # throw away any data before a opening brace
        try:
            open_brace_idx = self._buf.index('{')
        except ValueError:
            self._buf = six.u('')  # no brace found
        else:
            if open_brace_idx > 0:
                self._buf = self._buf[open_brace_idx:]

        try:
            event, idx = self._decoder.raw_decode(self._buf)
            self._buf = self._buf[idx:]
            return event
        except ValueError:
            return None
Parse the stream buffer and return either a single event or None