TransactionHandler nonspecial(Handle handle) {
        return bound.computeIfAbsent(handle, Unchecked.function(BoundLocalTransactionHandler::new));
    }
This <code>TransactionHandler</code> uses local JDBC transactions
demarcated explicitly on the handle and passed through to be handled
directly on the JDBC Connection instance.
core/src/main/java/org/jdbi/v3/core/transaction/LocalTransactionHandler.java