struct worker_thread *(*new_thread)(void); // default: xmalloc the struct
void (*free_thread)(struct worker_thread *t); // default: xfree
void (*init_thread)(struct worker_thread *t); // default: empty
struct worker_thread *(*new_thread)(void); // default: xmalloc the struct
void (*free_thread)(struct worker_thread *t); // default: xfree
void (*init_thread)(struct worker_thread *t); // default: empty