public com.google.protobuf.ByteString getKmsKeyBytes() {
        java.lang.Object ref = kmsKey_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          kmsKey_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
Immutable. The name of the Google Cloud KMS encryption key. For example,
`"projects/PROJECT_ID/locations/REGION/keyRings/KEY_RING/cryptoKeys/KEY_NAME"`.
The key must be in the same region as the workstation configuration.
</pre>

<code>string kms_key = 1 [(.google.api.field_behavior) = IMMUTABLE];</code>

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