public Builder mergeFrom(com.google.cloud.vertexai.api.CitationMetadata other) {
      if (other == com.google.cloud.vertexai.api.CitationMetadata.getDefaultInstance()) return this;
      if (citationsBuilder_ == null) {
        if (!other.citations_.isEmpty()) {
          if (citations_.isEmpty()) {
            citations_ = other.citations_;
            bitField0_ = (bitField0_ & ~0x00000001);
          } else {
            ensureCitationsIsMutable();
            citations_.addAll(other.citations_);
          }
          onChanged();
        }
      } else {
        if (!other.citations_.isEmpty()) {
          if (citationsBuilder_.isEmpty()) {
            citationsBuilder_.dispose();
            citationsBuilder_ = null;
            citations_ = other.citations_;
            bitField0_ = (bitField0_ & ~0x00000001);
            citationsBuilder_ =
                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders
                    ? getCitationsFieldBuilder()
                    : null;
          } else {
            citationsBuilder_.addAllMessages(other.citations_);
          }
        }
      }
      this.mergeUnknownFields(other.getUnknownFields());
      onChanged();
      return this;
    }
<pre>
A collection of source attributions for a piece of content.
</pre>

Protobuf type {@code google.cloud.vertexai.v1.CitationMetadata}
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/CitationMetadata.java