private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.FieldMask,
            com.google.protobuf.FieldMask.Builder,
            com.google.protobuf.FieldMaskOrBuilder>
        getReadMaskFieldBuilder() {
      if (readMaskBuilder_ == null) {
        readMaskBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.FieldMask,
                com.google.protobuf.FieldMask.Builder,
                com.google.protobuf.FieldMaskOrBuilder>(
                getReadMask(), getParentForChildren(), isClean());
        readMask_ = null;
      }
      return readMaskBuilder_;
    }
<pre>
Optional. Mask specifying which fields to read.
</pre>

<code>.google.protobuf.FieldMask read_mask = 5 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ListEndpointsRequest.java