'Consumes the payload portion of C{self._remainingData}.
If the payload is complete, checks for the trailing comma and
processes the payload. If not, raises an L{IncompleteNetstring}
exception.
@raise IncompleteNetstring: if the payload received so far
contains fewer characters than expected.
@raise NetstringParseError: if the payload does not end with a
comma.'

def _consumePayload(self):

    self._extractPayload()
    if (self._currentPayloadSize < self._expectedPayloadSize):
        raise IncompleteNetstring()
    self._checkForTrailingComma()
    self._state = self._PARSING_LENGTH
    self._processPayload()
