private void ensureContentsIsMutable() {
      if (!((bitField0_ & 0x00000002) != 0)) {
        contents_ = new java.util.ArrayList<com.google.cloud.vertexai.api.Content>(contents_);
        bitField0_ |= 0x00000002;
      }
    }
<pre>
Required. The fully qualified name of the publisher model or tuned model
endpoint to use.

Publisher model format:
`projects/{project}/locations/{location}/publishers/&#42;&#47;models/&#42;`

Tuned model endpoint format:
`projects/{project}/locations/{location}/endpoints/{endpoint}`
</pre>

<code>string model = 5 [(.google.api.field_behavior) = REQUIRED];</code>

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