var github.com/valyala/fastjson.valueNull

5 uses

	github.com/valyala/fastjson (current package)
		arena.go#L115: 	return valueNull
		parser.go#L157: 		return valueNull, s[len("null"):], nil
		parser.go#L975: 	valueNull  = &Value{t: TypeNull}
		update.go#L60: 		value = valueNull
		update.go#L107: 		v.a = append(v.a, valueNull)