public Builder clearDraftModel() {
        draftModel_ = getDefaultInstance().getDraftModel();
        bitField0_ = (bitField0_ & ~0x00000001);
        onChanged();
        return this;
      }
<pre>
Required. The resource name of the draft model.
</pre>

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

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