public Builder setSpeakingRate(double value) {

      speakingRate_ = value;
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
Optional. Input only. Speaking rate/speed, in the range [0.25, 2.0]. 1.0 is
the normal native speed supported by the specific voice. 2.0 is twice as
fast, and 0.5 is half as fast. If unset(0.0), defaults to the native 1.0
speed. Any other values &lt; 0.25 or &gt; 2.0 will return an error.
</pre>

<code>
double speaking_rate = 3 [(.google.api.field_behavior) = INPUT_ONLY, (.google.api.field_behavior) = OPTIONAL];
</code>

@param value The speakingRate to set.
@return This builder for chaining.
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/StreamingAudioConfig.java