private com.google.protobuf.SingleFieldBuilderV3<
              com.google.protobuf.Timestamp,
              com.google.protobuf.Timestamp.Builder,
              com.google.protobuf.TimestampOrBuilder>
          getLastModifiedBeforeFieldBuilder() {
        if (lastModifiedBeforeBuilder_ == null) {
          lastModifiedBeforeBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.protobuf.Timestamp,
                  com.google.protobuf.Timestamp.Builder,
                  com.google.protobuf.TimestampOrBuilder>(
                  getLastModifiedBefore(), getParentForChildren(), isClean());
          lastModifiedBefore_ = null;
        }
        return lastModifiedBeforeBuilder_;
      }
<pre>
If specified, only objects with a "last modification time" before this
timestamp and objects that don't have a "last modification time" are
transferred.
</pre>

<code>.google.protobuf.Timestamp last_modified_before = 6;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java