lang/c++/jsonschemas/tree2

{
  "name": "Node",
  "type": "record",
  "fields": [
    {
      "name": "payload",
      "type": "int",
      "default": 0
    },
    {
      "name": "edges",
      "type": {
        "type": "map",
        "values": "Node"
      }
    }
  ]
}