@java.lang.Override
      public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
        if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(machineType_)) {
          com.google.protobuf.GeneratedMessageV3.writeString(output, 1, machineType_);
        }
        if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(serviceAccount_)) {
          com.google.protobuf.GeneratedMessageV3.writeString(output, 2, serviceAccount_);
        }
        for (int i = 0; i < serviceAccountScopes_.size(); i++) {
          com.google.protobuf.GeneratedMessageV3.writeString(
              output, 3, serviceAccountScopes_.getRaw(i));
        }
        for (int i = 0; i < tags_.size(); i++) {
          com.google.protobuf.GeneratedMessageV3.writeString(output, 4, tags_.getRaw(i));
        }
        if (poolSize_ != 0) {
          output.writeInt32(5, poolSize_);
        }
        if (disablePublicIpAddresses_ != false) {
          output.writeBool(6, disablePublicIpAddresses_);
        }
        if (enableNestedVirtualization_ != false) {
          output.writeBool(7, enableNestedVirtualization_);
        }
        if (((bitField0_ & 0x00000001) != 0)) {
          output.writeMessage(8, getShieldedInstanceConfig());
        }
        if (bootDiskSizeGb_ != 0) {
          output.writeInt32(9, bootDiskSizeGb_);
        }
        if (((bitField0_ & 0x00000002) != 0)) {
          output.writeMessage(10, getConfidentialInstanceConfig());
        }
        if (pooledInstances_ != 0) {
          output.writeInt32(12, pooledInstances_);
        }
        getUnknownFields().writeTo(output);
      }
<pre>
Optional. The size of the boot disk for the VM in gigabytes (GB).
The minimum boot disk size is `30` GB. Defaults to `50` GB.
</pre>

<code>int32 boot_disk_size_gb = 9 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The bootDiskSizeGb.
java-workstations/proto-google-cloud-workstations-v1/src/main/java/com/google/cloud/workstations/v1/WorkstationConfig.java