Function parquet::decoding::get_decoder

pub fn get_decoder<T: DataType>(
    descr: ColumnDescPtr, 
    encoding: Encoding
) -> Result<Box<Decoder<T>>> where
    T: 'static, 

Gets a decoder for the column descriptor descr and encoding type encoding.

NOTE: the primitive type in descr MUST match the data type T, otherwise disastrous consequence could occur.