private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Timestamp,
            com.google.protobuf.Timestamp.Builder,
            com.google.protobuf.TimestampOrBuilder>
        getRecommendedNextDiffFieldBuilder() {
      if (recommendedNextDiffBuilder_ == null) {
        recommendedNextDiffBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Timestamp,
                com.google.protobuf.Timestamp.Builder,
                com.google.protobuf.TimestampOrBuilder>(
                getRecommendedNextDiff(), getParentForChildren(), isClean());
        recommendedNextDiff_ = null;
      }
      return recommendedNextDiffBuilder_;
    }
<pre>
The soonest the client should wait before issuing any diff
request. Querying sooner is unlikely to produce a meaningful diff.
Waiting longer is acceptable considering the use case.
If this field is not set clients may update as soon as they want.
</pre>

<code>.google.protobuf.Timestamp recommended_next_diff = 2;</code>
java-webrisk/proto-google-cloud-webrisk-v1/src/main/java/com/google/webrisk/v1/ComputeThreatListDiffResponse.java