public Builder clearCustomerEncryptionKey() {
      bitField0_ = (bitField0_ & ~0x00000001);
      customerEncryptionKey_ = null;
      if (customerEncryptionKeyBuilder_ != null) {
        customerEncryptionKeyBuilder_.dispose();
        customerEncryptionKeyBuilder_ = null;
      }
      onChanged();
      return this;
    }
<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>
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/BootDiskConfig.java