public com.google.cloud.tpu.v2alpha1.CustomerEncryptionKey getCustomerEncryptionKey() {
      if (customerEncryptionKeyBuilder_ == null) {
        return customerEncryptionKey_ == null
            ? com.google.cloud.tpu.v2alpha1.CustomerEncryptionKey.getDefaultInstance()
            : customerEncryptionKey_;
      } else {
        return customerEncryptionKeyBuilder_.getMessage();
      }
    }
<pre>
Optional. Customer encryption key for boot disk.
</pre>

<code>
.google.cloud.tpu.v2alpha1.CustomerEncryptionKey customer_encryption_key = 1 [(.google.api.field_behavior) = OPTIONAL];
</code>

@return The customerEncryptionKey.
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/BootDiskConfig.java