private void ensureRagFileIdsIsMutable() {
        if (!ragFileIds_.isModifiable()) {
          ragFileIds_ = new com.google.protobuf.LazyStringArrayList(ragFileIds_);
        }
        bitField0_ |= 0x00000002;
      }
<pre>
Optional. RagCorpora resource name.
Format:
`projects/{project}/locations/{location}/ragCorpora/{rag_corpus}`
</pre>

<code>
string rag_corpus = 1 [(.google.api.field_behavior) = OPTIONAL, (.google.api.resource_reference) = { ... }
</code>

@param value The bytes for ragCorpus to set.
@return This builder for chaining.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/VertexRagStore.java