copy_with_timeout() as implemented in v0.7.2 may exceed its deadline:

In here the timeout is only checked after the read operation is issued. However, a call to read() may block according to the documentation. If used on a reader that reads from a network socket, IIRC it will block waiting for data from the remote server until the underlying TCP timeout expires (5 minutes by default).

I believe this is a fundamental limitation of the approach; I am not aware of any ways to fix it without spawning an auxiliary thread or using an async runtime.

If a read timeout is desired, it should be configured on the socket explicitly instead.

If a timeout for the entire request is desired, it can be implemented either by spawning an auxiliary thread that interrupts the main thread (as done in attohttpc), or by setting the read timeout to the minimum of read timeout and the remaining time until the deadline for the entire request (as done in minreq).