public Builder clearChannelId() {
          channelId_ = getDefaultInstance().getChannelId();
          bitField0_ = (bitField0_ & ~0x00000001);
          onChanged();
          return this;
        }
<pre>
Required. The Slack channel ID.
</pre>

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

@return This builder for chaining.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/SlackSource.java