public Builder setUsage(java.lang.String value) {
        if (value == null) {
          throw new NullPointerException();
        }
        usage_ = value;
        bitField0_ |= 0x00000001;
        onChanged();
        return this;
      }
<pre>
Optional. Usage of the file contents. Options are TRAIN|VALIDATION|TEST,
or UNASSIGNED (by default) for auto split.
</pre>

<code>string usage = 2 [(.google.api.field_behavior) = OPTIONAL];</code>

@param value The usage to set.
@return This builder for chaining.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/DatasetInputConfig.java