would sendfile be better if we have to write data that is already in memory?

Question

i am having some data in user space memory buffer that i want to send through socket. i was reading about zero copy in Linux, was wondering it is possible to use it in this case or any optimisation possible here.

char buff[buffer_size]; // buffer already in memory (user space)
while (condition) {
  buff[(i++) % buffer_size] = 1; // do some changes in buffer
  write(sockfd, buff, buffer_size); // can we use sendfile here? would it give benefit?
}