public void doPrepare() {
// note for future: in anticompaction two different operations use the same Transaction, and
// both prepareToCommit()
// separately: the second prepareToCommit is ignored as a "redundant" transition. since it is
// only a checkpoint
// (and these happen anyway) this is fine but if more logic gets inserted here than is performed
// in a checkpoint,
// it may break this use case, and care is needed
checkpoint();
}
