Default constructor */

* Returns a reference to the element at the specified location, with bounds * checking. * * @return A reference to the element at the specifi

* Returns a reference to the last element of the array * * @return A reference to the last element of the array * @pre empty() == false */

* * { * "e": "depthUpdate", * "E": 123456789, * "s": "BNBBTC", * "U": 157, * "u": 160, * "b": * [ * ["0.0024", "10"] * ], * "a":

coin based futures { "symbols": [{ "symbol": "BTCUSD_PERP", "pair": "BTCUSD", "contractType": "PERPETUAL", "deliveryDate": 41334048

* Returns a constant reverse iterator to the first element of the reversed * array. It corresponds to the last element of the non-reversed array.

* { * "lastUpdateId": 19071881594, * "bids": [ * ["31603.76000000", "0.32990000"], * ["31603.75000000", "0.00090000"], * ["31603.63000

* Returns a constant reverse iterator to the element following the last * element of the reversed array. It corresponds to the element preceding th