Injecting server urls for test purposes

[rorymckinley]

Hello!

Firstly, thank you for building and maintaining this crate, it is much appreciated!

I would like to use the crate in a trivial little CLI - I am just trying to figure out how to structure my tests so that I don't end up spamming data.iana.org every time I run the tests. Would you be open to me submitting a change as follows?

• Adding an host_url: String to the Client struct.
• Adding a method to overwrite the host_url value
• Changing the fetch_bootstrap_* methods to build URLs using self.host_url

The above would allow me to point the Client at mockito or something like mountebank.

I am a Rust noob but happy to submit the change if you are happy with the change. Alternatively, if you have an alternative implementation in mind, I would be happy to go that way as well.

Or, of course, if there is some way to already do the above (and I have just not looked properly) - that would be even better! 😄

Thanks for your time!