Waits until read would not have to wait: a byte is there, the source ended, or it failed (the
read that follows says which). Nothing is consumed, so it needs no buffer.
Wait_Proc :: #type (data: *void) -> Io_ErrorWaits until read would not have to wait: a byte is there, the source ended, or it failed (the
read that follows says which). Nothing is consumed, so it needs no buffer.
Wait_Proc :: #type (data: *void) -> Io_Error