#define fd_wants_writes(FD) (((FD)->send.get != (FD)->send.put) || (FD)->state == IO_CONNECTING)
struct io_engine {
const char *name;
int (*init)(void);
void (*add)(struct io_fd *fd);
#define fd_wants_writes(FD) (((FD)->send.get != (FD)->send.put) || (FD)->state == IO_CONNECTING)
struct io_engine {
const char *name;
int (*init)(void);
void (*add)(struct io_fd *fd);