fixing ClassCastExceptions
Revert "Fix race condition where a transaction requests children to prepare before one or more chidren are done cancelling."

This reverts commit 9a200244d85f3257e295811e7e7b5e48d20c027e.
Reviewed and fixed commits: 9a200244d85f3257e295811e7e7b5e48d20c027e 4876dd84326a71e87477ec9879f3cccf8d03a6d5