TRADING channel in order to send trading messages.{
    "type": "CANCEL_ALL_ORDERS",
    "instrument_code": "BTC_EUR" // Optional
 }{
    "error": "no orders to cancel"
}{
    "error": "PAIR_ERROR",
    "payload": {
        "type": "CANCEL_ALL_ORDERS",
        "instrument_code": "BTC_PEPE"
    }
}{
    "channel_name": "TRADING",
    "type": "BOOKED",
    "details": "cancelling 2 orders"
}