public Builder setEndTime(com.google.protobuf.Timestamp value) {
          if (endTimeBuilder_ == null) {
            if (value == null) {
              throw new NullPointerException();
            }
            endTime_ = value;
          } else {
            endTimeBuilder_.setMessage(value);
          }
          bitField0_ |= 0x00000004;
          onChanged();
          return this;
        }
<pre>
Optional. The ending timestamp for messages to import.
</pre>

<code>.google.protobuf.Timestamp end_time = 3 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/SlackSource.java