Extract `Builder` from `Trace` (#545) #452

Job	Run time
test mdBook	40s
cargo test on ubuntu, rust stable	44s
cargo test on ubuntu, rust 1.78	51s
cargo test on macos, rust stable	45s
cargo test on macos, rust 1.78	51s
cargo test on windows, rust stable	2m 35s
cargo test on windows, rust 1.78	1m 45s
	8m 11s

Provide feedback