presto-kinesis/src/main/java/io/prestosql/plugin/kinesis/KinesisStreamFieldGroup.java/KinesisStreamFieldGroup/KinesisStreamFieldGroup
class KinesisStreamFieldGroup:    @JsonCreator
    public KinesisStreamFieldGroup(
            @JsonProperty("dataFormat") String dataFormat,
            @JsonProperty("fields") List<KinesisStreamFieldDescription> fields)
    {
        this.dataFormat = requireNonNull(dataFormat, "dataFormat is null");
        this.fields = ImmutableList.copyOf(requireNonNull(fields, "fields is null"));
    }