/** Creates an op that deletes the doc's current state. */
private DocOp createErasureOp() {
UncheckedDocOpBuffer builder = new UncheckedDocOpBuffer();
doc.toInitialization().apply(builder);
return DocOpInverter.invert(builder.finish());
}
private static DocOp createReplaceOp(DocOp erase, DocOp restore) {
try {
return Composer.compose(erase, restore);