private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.FieldMask,
            com.google.protobuf.FieldMask.Builder,
            com.google.protobuf.FieldMaskOrBuilder>
        getConfigMaskFieldBuilder() {
      if (configMaskBuilder_ == null) {
        configMaskBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.FieldMask,
                com.google.protobuf.FieldMask.Builder,
                com.google.protobuf.FieldMaskOrBuilder>(
                getConfigMask(), getParentForChildren(), isClean());
        configMask_ = null;
      }
      return configMaskBuilder_;
    }
<pre>
The list of fields in
[config][google.cloud.speech.v2.RecognizeRequest.config] that override the
values in the
[default_recognition_config][google.cloud.speech.v2.Recognizer.default_recognition_config]
of the recognizer during this recognition request. If no mask is provided,
all non-default valued fields in
[config][google.cloud.speech.v2.RecognizeRequest.config] override the
values in the recognizer for this recognition request. If a mask is
provided, only the fields listed in the mask override the config in the
recognizer for this recognition request. If a wildcard (`*`) is provided,
[config][google.cloud.speech.v2.RecognizeRequest.config] completely
overrides and replaces the config in the recognizer for this recognition
request.
</pre>

<code>.google.protobuf.FieldMask config_mask = 8;</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/RecognizeRequest.java