private com.google.protobuf.RepeatedFieldBuilderV3<
            com.google.cloud.vertexai.api.SlackSource.SlackChannels,
            com.google.cloud.vertexai.api.SlackSource.SlackChannels.Builder,
            com.google.cloud.vertexai.api.SlackSource.SlackChannelsOrBuilder>
        getChannelsFieldBuilder() {
      if (channelsBuilder_ == null) {
        channelsBuilder_ =
            new com.google.protobuf.RepeatedFieldBuilderV3<
                com.google.cloud.vertexai.api.SlackSource.SlackChannels,
                com.google.cloud.vertexai.api.SlackSource.SlackChannels.Builder,
                com.google.cloud.vertexai.api.SlackSource.SlackChannelsOrBuilder>(
                channels_, ((bitField0_ & 0x00000001) != 0), getParentForChildren(), isClean());
        channels_ = null;
      }
      return channelsBuilder_;
    }
<pre>
Required. The Slack channels.
</pre>

<code>
repeated .google.cloud.vertexai.v1.SlackSource.SlackChannels channels = 1 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/SlackSource.java