start Transaction Async
fun startTransactionAsync(request: TransactionRequest, configurer: Function<TransactionCall, TransactionCall>): TransactionHandle
Starts a transaction in the background. Use the returned handle to receive the final TransactionResult and to resolve deferred commit decisions.
Throws IllegalStateException if a pre-transaction wait (startPreTransaction/ startPreTransactionAsync/preResume) is still pending - continue it via PreTransactionResult.startTransaction instead, or call abort first to discard it.