pub unsafe extern "C" fn rocksdb_readoptions_set_iterate_upper_bound(
    readopts: *const DBReadOptionsOpaque, 
    k: *const u8, 
    kLen: usize
)pub unsafe extern "C" fn rocksdb_readoptions_set_iterate_upper_bound(
    readopts: *const DBReadOptionsOpaque, 
    k: *const u8, 
    kLen: usize
)