refactor(iroh): use boxed client to get rid of the C type parameter #8685

Job	Run time
check_semver	4m 43s
Checking docs	1m 17s
cargo deny	29s
Checking fmt	19s
clippy_check	2m 45s
Cross Build Only (armv7-linux-androideabi)	1m 18s
Cross Test (i686-unknown-linux-gnu)	2m 37s
Cross Build Only (aarch64-linux-android)	1m 3s
Minimal Supported Rust Version	1m 36s
Cross Build Only (x86_64-unknown-freebsd)	1m 7s
Run network simulations/benchmarks	6m 50s
Cross Build Only (x86_64-unknown-netbsd)	1m 8s
Build wasm32	33s
CI Test Suite / Tests (ubuntu-latest, stable, all)	2m 43s
CI Test Suite / Tests (windows-latest, stable, all, x86_64-pc-windows-msvc)	3m 53s
CI Test Suite / Tests (ubuntu-latest, stable, none)	2m 12s
CI Test Suite / Tests (windows-latest, stable, none, x86_64-pc-windows-msvc)	3m 57s
CI Test Suite / Tests (ubuntu-latest, stable, default)	3m 13s
CI Test Suite / Tests (windows-latest, stable, default, x86_64-pc-windows-msvc)	3m 39s
CI Test Suite / Tests (macOS-arm-latest, stable, all)	3m 9s
CI Test Suite / Tests (macOS-arm-latest, stable, none)	2m 54s
CI Test Suite / Tests (macOS-arm-latest, stable, default)	2m 51s
	54m 16s

Provide feedback