pub type uv_random_cb = Option<unsafe extern "C" fn(req: *mut uv_random_t, status: c_int, buf: *mut c_void, buflen: size_t)>;
pub enum uv_random_cb { None, Some(unsafe extern "C" fn(*mut uv_random_s, i32, *mut c_void, u64)), }
No value.
Some value of type T.
T