BACKWARD Compatibility Type does not support add optional field about schema-registry

[rayokota]

An optional field is a union of null and the type, such as "type": ["null", "string"]

[ThinhLe30]

already try it, it's the same response

[ThinhLe30]

old schema:

{
	"type": "record",
	"name": "user",
	"fields": [
		{"name": "name", "type": "string"},
		{"name": "favorite_number",  "type": "int"}
	]
}

new schema:

{
	"type": "record",
	"name": "user",
	"fields": [
		{"name": "name", "type": "string"},
		{"name": "favorite_number",  "type": "int"},
		{"name": "favorite_color", "type": ["null", "string"], "default": null}
	]
}

and the response:

:(((