This commit avoids copying HTTP headers when mutating an HTTP request. Instead, we're now unwrapping the `ReadOnlyHttpHeaders` (which is most likely backed by the native request headers). Issue: SPR-17250
This commit avoids copying HTTP headers when mutating an HTTP request. Instead, we're now unwrapping the `ReadOnlyHttpHeaders` (which is most likely backed by the native request headers). Issue: SPR-17250