void start() {
        try {
            socket.startHandshake();
            input = socket.getInputStream();
            output = socket.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
Client-side endpoint. Provides basic services for sending/receiving messages from the client
socket.
benchmark-base/src/main/java/org/conscrypt/ClientEndpoint.java