public Builder clearRevisionId() {
      revisionId_ = getDefaultInstance().getRevisionId();
      bitField0_ = (bitField0_ & ~0x00000002);
      onChanged();
      return this;
    }
<pre>
Required. The revision id of deployment to roll back to.
</pre>

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

@return This builder for chaining.
java-telcoautomation/proto-google-cloud-telcoautomation-v1alpha1/src/main/java/com/google/cloud/telcoautomation/v1alpha1/RollbackDeploymentRequest.java