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>
The key of the label attached to the product. Cannot be empty and cannot
exceed 128 bytes.
</pre>

<code>string key = 1;</code>

@return The bytes for key.
java-vision/proto-google-cloud-vision-v1p3beta1/src/main/java/com/google/cloud/vision/v1p3beta1/Product.java