message.json

{
    "schema": {
        "type": "struct",
        "fields": [{
            "type": "int32",
            "optional": false,
            "field": "id"
        }, {
            "type": "struct",
            "name": "data",
            "optional": false,
            "fields": [{
               "type": "string",
               "name": "hello",
               "optional":false
            }]
        }],
        "optional": false,
        "name": "foobar"
    },
    "payload": {
        "id": 10000,
        "data": {"hello":"world"}
    }
}