Kinesis Firehose lambda api doesn't support routing to multiple table for iceberg

[amalakar]

Is your feature request related to a problem? Please describe. As per: https://docs.aws.amazon.com/firehose/latest/dev/apache-iceberg-format-input-record-different.html In order to set the target table while processing via lambda needs to set metadata as:

    "metadata":{
        "otfMetadata":{
            "destinationTableName":"gameevents",
            "destinationDatabaseName":"PlayerSpawn",
            "operation":"insert"
        }
    }

But the response metadata struct only supports partition keys https://github.com/aws/aws-lambda-go/blob/1ba09afd7523e0d5a8a2e2fb58ddb8ec8b92ebb7/events/firehose.go#L40

type KinesisFirehoseResponseRecord struct {
.....
    Metadata KinesisFirehoseResponseRecordMetadata `json:"metadata"`
}

type KinesisFirehoseResponseRecordMetadata struct {
    PartitionKeys map[string]string `json:"partitionKeys"`
}

Describe the solution you'd like Please support otfMetadata as part of metadata for lambda response object.