All the lease REST APIs support the access conditions (etag and time based), but only the acquireLease proxy API allows the user to specify access conditions.
The fix would be to rename AcquireLeaseOptions to be something more generic, like LeaseOptions, and use that LeaseOptions for all the lease proxy APIs.
This issue can be broken down into several parts.
a. shall we support access conditions now? What is the benefit of it? What if we do not have it?
b. If we want to support it, what is the right design?
c. Does PHP have the same problem?
d. How to test it?
The msdn documentation is here.