post https://app.skuvault.com/api/inventory/updateExternalWarehouseQuantities
Severe throttling
Set the quantity of SKUs in a specified external warehouse. Updating an external warehouse's quantities will overwrite any existing quantities: missed SKU will be zeroed out. In case the SKU was duplicated in the request only the last inventory record will be applied. The limit is 200,000 SKUs per call.
This request overwrites the entire external warehouse.
Any SKU in an external warehouse that is omitted from the next request will be removed from said warehouse.