public Map<?, ?> readMap(ClickHouseColumn column) throws IOException {
        int len = readVarInt(input);
        if (len == 0) {
            return Collections.emptyMap();
        }

        ClickHouseColumn keyType = column.getKeyInfo();
        ClickHouseColumn valueType = column.getValueInfo();
        LinkedHashMap<Object, Object> map = new LinkedHashMap<>(len);
        for (int i = 0; i < len; i++) {
            Object key = readValue(keyType);
            Object value = readValue(valueType);
            map.put(key, value);
        }
        return map;
    }
Reads a map.
@param column - column information
@return a map
@throws IOException when IO error occurs
client-v2/src/main/java/com/clickhouse/client/api/data_formats/internal/BinaryStreamReader.java