Transaction scheduling code.
This crate implements 3 solana-runtime traits (InstalledScheduler, UninstalledScheduler and
InstalledSchedulerPool) to provide a concrete transaction scheduling implementation
(including executing txes and committing tx results).
At the highest level, this crate takes SanitizedTransactions via its schedule_execution()
and commits any side-effects (i.e. on-chain state changes) into the associated Bank via
solana-ledger's helper function called execute_batch().