public Builder mergeMinDuration(com.google.protobuf.Duration value) {
        if (minDurationBuilder_ == null) {
          if (((bitField0_ & 0x00000001) != 0)
              && minDuration_ != null
              && minDuration_ != com.google.protobuf.Duration.getDefaultInstance()) {
            getMinDurationBuilder().mergeFrom(value);
          } else {
            minDuration_ = value;
          }
        } else {
          minDurationBuilder_.mergeFrom(value);
        }
        if (minDuration_ != null) {
          bitField0_ |= 0x00000001;
          onChanged();
        }
        return this;
      }
<pre>
Optional. Defines the minimum duration of the guarantee. If specified,
the requested resources will only be provisioned if they can be
allocated for at least the given duration.
</pre>

<code>.google.protobuf.Duration min_duration = 1 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java