Function git2::transport::register

pub unsafe fn register<F>(prefix: &str, factory: F) -> Result<(), Error> where
    F: Fn(&Remote<'_>) -> Result<Transport, Error> + Send + Sync + 'static, 

Add a custom transport definition, to be used in addition to the built-in set of transports that come with libgit2.

This function is unsafe as it needs to be externally synchronized with calls to creation of other transports.