launch voice input or delete_or_backspace by application key

karabiner.json

"global": {
	......
},
"profiles": [{
	"complex_modifications": {
		"parameters": {
			......
			"basic.to_if_held_down_threshold_milliseconds": 500
		},
		"rules": [
			{
				"manipulators": [{
					"description": "launch voice input or delete_or_backspace",
					"from": {
						"key_code": "application"
					},
					"to_if_held_down": [
						{
							"key_code": "fn",
							"halt": true
						},
						{
							"key_code": "fn"
						}
					],
					"to_after_key_up": [{
							"key_code": "delete_or_backspace"
						}
					],
					"type": "basic"
				}]
			}
	    ]
	}
}]