code: public GelfMessage build() {
  
          GelfMessage gelfMessage = new PoolingGelfMessage(shortMessage, fullMessage, javaTimestamp, level, poolHolder);
          gelfMessage.addFields(additionalFields);
          gelfMessage.setMaximumMessageSize(maximumMessageSize);
          gelfMessage.setVersion(version);
          gelfMessage.setHost(host);
          gelfMessage.setJavaTimestamp(javaTimestamp);
          gelfMessage.setFacility(facility);
          gelfMessage.setAdditionalFieldTypes(additionalFieldTypes);
  
          return gelfMessage;
      }
docs: Build a new Gelf message based on the builder settings.
  
  @return GelfMessage