Records latencies for the first transaction processing leg. Transaction Leg One includes time spent from the point where the first message of a transaction is received to submission of send/store commit. It includes message processing and and any overhead associated with transactional book keeping done by the engine. Note that the each transaction leg is a portion of the overall commit time that is processed on the Aep Engine's thread. The sum of the transaction leg stats are important in that they determine the overal throughput that an application can sustain in terms of transactions per second.