presto-redis/src/main/java/io/prestosql/plugin/redis/decoder/hash/HashRedisRowDecoderFactory.java/HashRedisRowDecoderFactory/chooseFieldDecoders
class HashRedisRowDecoderFactory:    private Map<DecoderColumnHandle, RedisFieldDecoder<String>> chooseFieldDecoders(Set<DecoderColumnHandle> columns)
    {
        return columns.stream()
                .collect(ImmutableMap.toImmutableMap(identity(), this::chooseFieldDecoder));
    }