MarketDepthData

Field	Type	Description
`position`	`int32`	The number of positions held
`operation`	`int32`	Indicates a change in the row’s value.:
`side`	`int32`	0 for ask, 1 for bid
`price`	`double`	The order’s price
`size`	`string`	Represents volume of the order data.
`marketMaker`	`string`	The exchange holding the order if isSmartDepth is True, otherwise the MPID of the market maker
`isSmartDepth`	`bool`	Flag indicates that this is smart depth request