Function librocksdbsys::crocksdb_approximate_memtable_stats

pub unsafe extern "C" fn crocksdb_approximate_memtable_stats(
    db: *const DBInstance, 
    range_start_key: *const u8, 
    range_start_key_len: size_t, 
    range_limit_key: *const u8, 
    range_limit_key_len: size_t, 
    count: *mut uint64_t, 
    size: *mut uint64_t
)