public Builder mergeMetadata(com.google.cloud.visionai.v1.RequestMetadata value) {
      if (metadataBuilder_ == null) {
        if (requestCase_ == 2
            && request_ != com.google.cloud.visionai.v1.RequestMetadata.getDefaultInstance()) {
          request_ =
              com.google.cloud.visionai.v1.RequestMetadata.newBuilder(
                      (com.google.cloud.visionai.v1.RequestMetadata) request_)
                  .mergeFrom(value)
                  .buildPartial();
        } else {
          request_ = value;
        }
        onChanged();
      } else {
        if (requestCase_ == 2) {
          metadataBuilder_.mergeFrom(value);
        } else {
          metadataBuilder_.setMessage(value);
        }
      }
      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