public com.google.protobuf.ByteString getKeyBytes() {
      java.lang.Object ref = key_;
      if (ref instanceof String) {
        com.google.protobuf.ByteString b =
            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
        key_ = b;
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
<pre>
Key for the guest attribute entry.
</pre>

<code>string key = 2;</code>

@return The bytes for key.
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/GuestAttributesEntry.java