A computing device has one or more processors and memory storing programs executed by the one or more processors. The computing device initializes a main application on a first thread. The main application has a first synchronous connection with a target application. After the main application performs one or more operations at the target application through the first synchronous connection, the computing device initializes an assistant process on a second thread. The assistant process has a second synchronous connection with the target application and an asynchronous connection with the main application. After receiving a request from the main application through the asynchronous connection, the assistant process performs one or more operations at the target application through the second synchronous connection.