@SuppressWarnings({"rawtypes"})
    protected com.google.protobuf.MapFieldReflectionAccessor internalGetMapFieldReflection(
        int number) {
      switch (number) {
        case 7:
          return internalGetCustomMetadata();
        default:
          throw new RuntimeException("Invalid map field number: " + number);
      }
    }
<pre>
Describes options for object metadata update.
</pre>

Protobuf type {@code google.cloud.storagebatchoperations.v1.PutMetadata}
java-storagebatchoperations/proto-google-cloud-storagebatchoperations-v1/src/main/java/com/google/cloud/storagebatchoperations/v1/PutMetadata.java