test/org/apache/pig/builtin/avro/schema/recordInMap.avsc

{
    "name" : "recordInMap",
    "namespace" : "org.apache.pig.test.builtin",
    "type" : "record",
    "fields" : [
        {"name" : "key", "type" : "string"},
        {"name" : "value", "type" : "int"},
        {
            "name" : "parameters",
            "type": {
                "type": "map",
                "values": {
                    "type": "record",
                    "name": "A",
                    "fields": [
                        {
                            "name": "id",
                            "type": [
                                "null",
                                "int"
                            ]
                        }
                    ]
                }
            }
        }
    ]
}