AccessViolationException then using StringComparator with ColumnFamily

[bill3code]

This code example throw exception with RocksDbSharp.StringComparator but without it works correctly.

            var options = new RocksDbSharp.DbOptions()
              .SetCreateIfMissing(true)
              .SetCreateMissingColumnFamilies(true);

            var bbto = new RocksDbSharp.BlockBasedTableOptions()
               .SetFilterPolicy(RocksDbSharp.BloomFilterPolicy.Create(20, false))
               .SetWholeKeyFiltering(false)
               .SetCacheIndexAndFilterBlocks(true);

            var columnFamilies = new RocksDbSharp.ColumnFamilies
            {
                 { "cf1", new RocksDbSharp.ColumnFamilyOptions()
                    .SetCompression(RocksDbSharp.CompressionTypeEnum.rocksdb_no_compression)
                    .SetComparator( new RocksDbSharp.StringComparator(StringComparer.InvariantCultureIgnoreCase)) //if commented - works fine
                    .SetBlockBasedTableFactory(bbto)
                },
            };
            using (var db = RocksDbSharp.RocksDb.Open(options, dbPath, columnFamilies))
            {
                Random rand = new Random(42);

                var cf1 = db.GetColumnFamily("cf1");

                for (int i = 0; i < 100000; ++i)
                {
                    string k = rand.Next(100000000).ToString();
                    byte[] key = Encoding.UTF8.GetBytes(k);
                    byte[] value = db.Get(key, cf1);
                    if (value == null)
                    {
                        db.Put(key, BitConverter.GetBytes(i), cf1);
                    }
                    else
                        Console.WriteLine(BitConverter.ToInt32(value, 0));
                }
            }

This error is not always reproduced!!! PS Windows x64