"<-chan TYPE" is the receive end, "chan<- TYPE" is the send end, "chan TYPE" without an arrow can be used for either.

close() on a chan is "indicate end-of-transmission"; you should only ever use it from the send end. There is no way to explicitly "close" the receive end.

You can use `select` to do a non-blocking sends/receives, but yeah normal sends/receives are blocking.