Fix for serious sinchronization bug
#objectForBorrow is transformed and renamed to unsafeBorrow with fixed logic:
Remove of idle object and add it to the borrow is now atomic operation.
Same idea is appliyed to return: operation.
#objectForBorrow is transformed and renamed to unsafeBorrow with fixed logic:
Remove of idle object and add it to the borrow is now atomic operation.
Same idea is appliyed to return: operation.