Since IO Multiplexing in go is based on Edge-triggered epoll, you always need to do a write/read syscall (it happens underneath) before blocking the goroutine to arm the epoll to poll that specific FD. Also this approach relies on parking/unparking the goroutine and there is no way around it, since it is part of the runtime.

One way go can make it nonblocking is to do the read/write and return the result immediately, but this kind of call requires a call back function to be provided, so instead of parking/unparking the goroutine, the call back function is called (either directly or by "go cb_function"), It can be tricky to make it work, since the initial goroutine might not be allowed to call read on FD anymore (maybe exit from the goroutine if the read was unsuccessful). In addition, you still need to provide a buffer to read from, the 1 byte trick works though, but the buffer management can be done either if the read was successful or in the call back function. Also this approach makes the programming asynchronous and similar to event programming.