Feature Request: Allow other platforms to inject code to handle timezone related information / functionality

[hax0kartik]

Hi,

I work with the compilers team for VxWorks(https://www.windriver.com/products/vxworks) and we want to add VxWorks support to this crate. Internally, we have a crate called as VXAL which serves as an abstraction layer. It uses OS specific API(s) and processes to query the timezone information. (It could be from the build process or from the kernel) However, this crate is strictly internal and cannot be pushed to crates.io as it contains sensitive information.

I would like to see some method to dynamically give this crate the information it needs.

Please check PR #173 and/or this comment #173 (comment) for further info.

Thanks!

[hax0kartik]

Checking further on the comment by @lopopolo, getrandom crate allows one to dynamically inject information by using a custom-backend and within this custom backend, it makes of use of an extern rust function to get the information it needs. (https://github.com/rust-random/getrandom/blob/8edf6e4be124a92676cfc6eab269ef08c6215cfe/src/backends/custom.rs) I think this should be doable with iana-time-zone as well. The custom backend could make use of a similar "extern" function to get the timezone.