Add configurable event_hooks for the httpx layer for observability or logging #95
Description
Is your feature request related to a problem? Please describe.
While thinking about this problem for another platform we maintain, I came across event_hooks in httpx.
We should make this configurable for the gallagher clients in case the user wants to add observability or logging for their implementation.
I don't believe the library should bother implementing the logging as a solution, it can provide reference implementations but not a solution.
Describe the solution you'd like
Modify the API so the developer can pass hooks into the initialisation which are called by the httpx layer upon requests placed and responses received.
In the case of httpx these work as interceptors where the developer can add additional headers etc.
Note that we will have to find a reliable mechanism to identify requests so we can perform operations like logging the body against other metadata, see also #2
Describe alternatives you've considered
NA
Additional context
NA