removeListeners (cbGID) {
    delete this._listeners[cbGID]
  }
Remove all listeners by callback group ID

@param {string} cbGID - callback group to remove
@example
await ws.subscribeTrades({ symbol: 'tBTCUSD', cbGID: 42 })
await ws.subscribeTrades({ symbol: 'tLEOUSD', cbGID: 42 })
await ws.subscribeTrades({ symbol: 'tETHUSD', cbGID: 42 })

// ...

ws.removeListeners(42)