Function unqlite_sys::unqlite_kv_cursor_key_callback

pub unsafe extern "C" fn unqlite_kv_cursor_key_callback(
    pCursor: *mut unqlite_kv_cursor, 
    xConsumer: Option<unsafe extern "C" fn(_: *const c_void, _: c_uint, _: *mut c_void) -> c_int>, 
    pUserData: *mut c_void
) -> c_int