public Builder mergeNetworkConfig(com.google.cloud.tpu.v2.NetworkConfig value) {
      if (networkConfigBuilder_ == null) {
        if (((bitField0_ & 0x00000040) != 0)
            && networkConfig_ != null
            && networkConfig_ != com.google.cloud.tpu.v2.NetworkConfig.getDefaultInstance()) {
          getNetworkConfigBuilder().mergeFrom(value);
        } else {
          networkConfig_ = value;
        }
      } else {
        networkConfigBuilder_.mergeFrom(value);
      }
      if (networkConfig_ != null) {
        bitField0_ |= 0x00000040;
        onChanged();
      }
      return this;
    }
<pre>
Network configurations for the TPU node. network_config and network_configs
are mutually exclusive, you can only specify one of them. If both are
specified, an error will be returned.
</pre>

<code>.google.cloud.tpu.v2.NetworkConfig network_config = 36;</code>
java-tpu/proto-google-cloud-tpu-v2/src/main/java/com/google/cloud/tpu/v2/Node.java