private Class[] getArgTypes(Request request, boolean addStreamHandler) {
        ProtocolStringList argTypesList = request.getArgTypesList();

        int size = addStreamHandler ? argTypesList.size() + 1 : argTypesList.size();
        Class[] argTypes = new Class[size];

        for (int i = 0; i < argTypesList.size(); i++) {
            String typeName = argTypesList.get(i);
            argTypes[i] = ClassTypeUtils.getClass(typeName);
        }

        if (addStreamHandler) {
            argTypes[size - 1] = SofaStreamObserver.class;
        }
        return argTypes;
    }
Get argument types from request.
@param request original request
@param addStreamHandler Whether add StreamHandler as the first method param.
<p>
For server stream call, the StreamHandler won't be transported.
To make the argument list conform to the method definition, we need to add it as first method param manually.

@return param types of target method
remoting/remoting-triple/src/main/java/com/alipay/sofa/rpc/server/triple/GenericServiceImpl.java