setting a session header obliterates all other session headers

Apps may need to have several session headers. at the moment, all prior session headers are reset (deleted) upon setting of any header.

This is not necessary. If an app needs to remove all headers, it can call `$session.rest`.

I would like to request the more general behavior of only changing the header supplied to `$session.set` at that time.

This also happens on the Android side; I hope this bug can serve for both platforms, but can file one separately if necessary.

Locate the implementations of $session.set and $session.rest on the iOS side, then check the corresponding Android session handling mentioned in the issue. Verify how existing headers are stored and replaced; done means setting one header preserves the others while $session.rest still removes them all on both platforms.

Written by the indexing model from the issue text.