private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Timestamp,
              com.google.protobuf.Timestamp.Builder,
              com.google.protobuf.TimestampOrBuilder>
          getExpireTimeFieldBuilder() {
        if (expireTimeBuilder_ == null) {
          expireTimeBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Timestamp,
                  com.google.protobuf.Timestamp.Builder,
                  com.google.protobuf.TimestampOrBuilder>(
                  getExpireTime(), getParentForChildren(), isClean());
          expireTime_ = null;
        }
        return expireTimeBuilder_;
      }
<pre>
The cache lifetime for the returned match. Clients must not cache this
response past this timestamp to avoid false positives.
</pre>

<code>.google.protobuf.Timestamp expire_time = 3;</code>
java-webrisk/proto-google-cloud-webrisk-v1/src/main/java/com/google/webrisk/v1/SearchHashesResponse.java