@java.lang.Override
    public com.google.protobuf.ByteString getDatetimeValueBytes() {
      java.lang.Object ref = "";
      if (valueCase_ == 5) {
        ref = value_;
      }
      if (ref instanceof String) {
        com.google.protobuf.ByteString b =
            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
        if (valueCase_ == 5) {
          value_ = b;
        }
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
<pre>
Value of date time type annotation.
</pre>

<code>string datetime_value = 5;</code>

@return The bytes for datetimeValue.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/AnnotationValue.java