Equivalent of `assert_cmd::Command::write_stdin` with extension traits

[asasine]

Based on asasine/spongebob#37, I was trying to update my tests to integration tests and use assert_cmd::cargo::CommandCargoExt::cargo_bin instead of assert_cmd::Command::cargo_bin however I use the write_stdin API. Is there an equivalent extension method or recommended pattern I should use to replace that type?