public com.google.protobuf.ByteString getChannelBytes() {
        java.lang.Object ref = channel_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          channel_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
The delivery channel for the event notification, only pub/sub topic is
supported now.
Example channel:
[//pubsub.googleapis.com/projects/visionai-testing-stable/topics/test-topic]
</pre>

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

@return The bytes for channel.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/ApplicationConfigs.java