code: private final State onConsumeHColon(final Buffer buffer) {
          try {
              if (SipParser.expectHCOLONStreamFriendly(buffer) == -1) {
                  return State.CONSUME_HCOLON;
              }
              return State.CONSUME_SWS_AFTER_HCOLON;
          } catch (final SipParseException e) {
              throw e;
          }
      }
docs: Consume HCOLON but we need to be slightly smarter than what the SipParser
  is offering up since we may run out of bytes from the stream just as we
  received the ':' and as such, we also need to be prepared to continue
  the "other half" of the {@link SipParser#expectHCOLON(Buffer)}.
  
  @param buffer
  @return