private Object getAppResponse(Method method, SofaResponse response) {
        if (response.isError()) {
            throw new SofaRpcException(RpcErrorType.SERVER_UNDECLARED_ERROR, response.getErrorMsg());
        }
        Object ret = response.getAppResponse();
        if (ret instanceof Throwable) {
            throw new SofaRpcRuntimeException((Throwable) ret);
        } else {
            if (ret == null) {
                ret = ClassUtils.getDefaultPrimitiveValue(method.getReturnType());
            }
        }
        return ret;
    }
Resolve method invoke args into request for bidirectional stream calls.

@param sofaRequest             SofaRequest
@param serviceMethod           Target service method
@param serverStreamPushHandler The StreamHandler used to push a message to a client. It's a wrapper for {@link StreamObserver}, and encode method return value to {@link Response}.
remoting/remoting-triple/src/main/java/com/alipay/sofa/rpc/server/triple/GenericServiceImpl.java