outboundAccountPosition is sent any time an account balance has changed and contains the assets that were possibly changed by the event that generated the balance change.
{"e":"outboundAccountPosition",//Event type"E":1564034571105,//Event Time"u":1564034571073,//Time of last account update"U":1027053479517,// time updateID"B":[//Balances Array{"a":"ETH",//Asset"f":"10000.000000",//Free"l":"0.000000"//Locked}]}