Overridable fn to get client IP address

[CaptainCodeman]

e.g. for cloudflare, when it would be in a http header (True-Client-IP?) instead of using SvelteKit's event.getClientAddress()

[CaptainCodeman]

I wonder if this is required, or comes down to a configuration issue? The example given at https://kit.svelte.dev/docs/adapter-node#environment-variables-addressheader-and-xffdepth is for True-Client-IP so it looks like SvelteKit / the adapter, should be handling this.