public Builder mergeRecommendedNextDiff(com.google.protobuf.Timestamp value) {
      if (recommendedNextDiffBuilder_ == null) {
        if (((bitField0_ & 0x00000020) != 0)
            && recommendedNextDiff_ != null
            && recommendedNextDiff_ != com.google.protobuf.Timestamp.getDefaultInstance()) {
          getRecommendedNextDiffBuilder().mergeFrom(value);
        } else {
          recommendedNextDiff_ = value;
        }
      } else {
        recommendedNextDiffBuilder_.mergeFrom(value);
      }
      if (recommendedNextDiff_ != null) {
        bitField0_ |= 0x00000020;
        onChanged();
      }
      return this;
    }
<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-v1beta1/src/main/java/com/google/webrisk/v1beta1/ComputeThreatListDiffResponse.java