decreasePosition()

decreasePosition() is a function to create new leverage position for specific pair.

By calling decreasePosition function, we close leverage open position from vault.

Router is a manager of vault.

Here is a description of the arguments:

function decreasePosition(
     bytes32 _tradePairId,
     uint256 _collateralDelta,
     uint256 _sizeDelta,
     bool _isLong,
     address _receiver)