presto-main/src/main/java/io/prestosql/sql/planner/LocalExecutionPlanner.java/LocalExecutionPlanner/createRemoteSource
class LocalExecutionPlanner:        private PhysicalOperation createRemoteSource(RemoteSourceNode node, LocalExecutionPlanContext context)
        {
            if (!context.getDriverInstanceCount().isPresent()) {
                context.setDriverInstanceCount(getTaskConcurrency(session));
            }

            OperatorFactory operatorFactory = new ExchangeOperatorFactory(
                    context.getNextOperatorId(),
                    node.getId(),
                    exchangeClientSupplier,
                    new PagesSerdeFactory(metadata.getBlockEncodingSerde(), isExchangeCompressionEnabled(session)));

            return new PhysicalOperation(operatorFactory, makeLayout(node), context, UNGROUPED_EXECUTION);
        }