SQLConnection.x(...) for each PostgresClient.x(AsyncResult<SQLConnection> tx, ...)

postgresClient.startTx(tx -> {
  postgresClient.getByIdAsStringForUpdate(tx, FOO, id, get -> {
    if (get.failed()) {
      // error handling
      return;
    }
    postgresClient.save(tx, FOO, xPojo, saved -> {
      if (saved.failed()) {
        // error handling
        return;
      }
      postgresClient.endTx(tx, endTx -> {
        if (endTx.failed()) {
          // error handling
          return;
        }
        // success handling
      });
    });
  });
});

future = postgresClient.startTx().compose(conn -> {
  return conn.getByIdAsStringForUpdate(FOO, id)
  .compose(get -> conn.save(FOO, xPojo))
  .compose(save -> conn.endTx());
});
future. ...  // handle success and error

future = postgresClient.withTransaction(conn -> conn
  .getByIdAsStringForUpdate(FOO, id)
  .compose(get -> conn.save(FOO, xPojo)));
future. ... // handle success and error

public void save(AsyncResult<SQLConnection> sqlConnection, String table, Object entity, Handler<AsyncResult<String>> replyHandler)

public Future<String> save(String table, Object entity)

public void rollbackTx(AsyncResult<SQLConnection> trans, Handler<AsyncResult<Void>> done)

public Future<Void> rollbackTx()