Who can clarify the meaning of this field?
https://binance-docs.github.io/apidocs/futures/en/#event-order-update
Json response example:
{
"e":"ORDER_TRADE_UPDATE",
"T":1638480526910,
"E":1638480526918,
"o": {
"s":"ALGOUSDT",
"c":"ios_st_nbnKYvhew7OEU8t",
"S":"BUY",
"o":"LIMIT",
"f":"GTC",
"q":"1000",
"p":"1.8500",
"ap":"0",
"sp":"0",
"x":"NEW",
"X":"NEW",
"i":4167877654,
"l":"0",
"z":"0",
"L":"0",
"T":1638480526910,
"t":0,
"b":"2929.99999",
"a":"3311.99999",
"m":false,
"R":false,
"wt":"CONTRACT_PRICE",
"ot":"LIMIT",
"ps":"BOTH",
"cp":false,
"rp":"0",
"pP":false,
"si":75110527,
"ss":1,
"st":"OTO"
}
}