{"namespace": "example.avro",
 "type": "record",
 "name": "User",
 "fields": [
     {"name": "name", "type": "string"},
     {"name": "favorite_number",  "type": ["int", "null"]},
     {"name": "favorite_colors",  "type": { "type": "array", "items": ["string","null"] }, "default": [] }
 ]
}