default RowType shardKeysToRowType(Collection<String> shardKeys) {
        DataTypes.Field[] fields =
                shardKeys.stream()
                        // We cannot get the exact type of the shard key, only the ordering of the
                        // shard index.
                        // Use the INT type as a placeholder.
                        .map(key -> DataTypes.FIELD(key, DataTypes.INT()))
                        .toArray(DataTypes.Field[]::new);
        return (RowType) DataTypes.ROW(fields).getLogicalType();
    }
The {@link MongoDBChunkSplitter} used to split collection into a set of chunks for MongoDB data
source.
Copy from com.ververica:flink-connector-mongodb-cdc:2.3.0.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/mongodb-cdc/src/main/java/org/apache/inlong/sort/cdc/mongodb/source/assigners/splitters/SplitStrategy.java