public Builder clearUsage() {
        usage_ = getDefaultInstance().getUsage();
        bitField0_ = (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>

@return This builder for chaining.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/DatasetInputConfig.java