public Builder setMetadata(
        com.google.cloud.visionai.v1.RequestMetadata.Builder builderForValue) {
      if (metadataBuilder_ == null) {
        request_ = builderForValue.build();
        onChanged();
      } else {
        metadataBuilder_.setMessage(builderForValue.build());
      }
      requestCase_ = 2;
      return this;
    }
<pre>
The first message of the streaming rpc including the request metadata.
</pre>

<code>.google.cloud.visionai.v1.RequestMetadata metadata = 2;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/SendPacketsRequest.java