@org.apache.thrift.annotation.Nullable
  public java.lang.Object getFieldValue(_Fields field) {
    switch (field) {
    case CATEGORY:
      return getCategory();

    case MESSAGE:
      return getMessage();

    }
    throw new java.lang.IllegalStateException();
  }
Returns true if field message is set (has been assigned a value) and false otherwise
zipkin-collector/scribe/src/main/java/zipkin2/collector/scribe/generated/LogEntry.java