Cant smoothly extend RestApplication without being stuck with RestComponent as well.

https://github.com/loopbackio/loopback-next/blob/2661354cb67560be32558f118fbd9164167c8d86/packages/rest/src/rest.application.ts#L94

Wanting to extend RestApplication to override one or another method and I'd also like to extend RestComponent and override a thing or two. Not really seeing a way to do it with the way this is coded. There are a bunch of patterns that could rectify this. Instead I'm having to entirely copy the RestApplication class to achieve this.

Noting. Will add more detail shortly. :)

Start with packages/rest/src/rest.application.ts around line 94, the location linked in the issue. Clarify the desired independent extension behavior for RestApplication and RestComponent, then identify the project tests covering these classes; done should provide a supported alternative to copying the entire RestApplication class.

Written by the indexing model from the issue text.