@java.lang.Override
  public int getSerializedSize() {
    int size = memoizedSize;
    if (size != -1) return size;

    size = 0;
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, name_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(sourceText_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, sourceText_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(targetText_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(3, targetText_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(usage_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(4, usage_);
    }
    size += getUnknownFields().getSerializedSize();
    memoizedSize = size;
    return size;
  }
<pre>
Output only. Usage of the sentence pair. Options are TRAIN|VALIDATION|TEST.
</pre>

<code>string usage = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>

@return The bytes for usage.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/Example.java