Unit tests and mocking

[simonmcl]

Theres no way to pass in a URLSession into any of the functions or constructors. This is how most libraries expose the ability to mock URL requests so that code can be unit tested.

Is there any other method available to mock requests that i've missed?

If not, please update the library to allow me to pass in my own URLSession so I can create my own mocks

[simonmcl]

@rathishubham7