Help needed to understand the customization scheme from P3826

[MiroPalmu]

In order to understand the machinery of s&r, I have been reading through the evolution of the proposed customization mechanisms: P2300 -> P2999 -> P3718 -> P3826

As seen from the number of papers on the subject, it is not simple. I have taken inline_scheduler implementation from P2300 and tried to add execution domain which 'transforms' each sender by printing their names and then returning the same sender. For most cases the customization works but it does not work/compile with the 'problematic example' from P3718 and P3826. For life of me I can not figure out why.

Here is the code (https://godbolt.org/z/xdMzK64Eq):

#include <meta>
#include <print>

#include "stdexec/execution.hpp"

struct Domain {
    template <typename S, typename... Env>
    static constexpr auto transform_sender(stdexec::set_value_t, S&& snd,
                                           const Env&... env) {
        std::println("domain set_value: {} {}",
                     std::meta::display_string_of(^^decltype(snd)),
                     sizeof...(env));

        return (S&&)snd;
    }
};

struct inline_scheduler {
    template <class R>
    struct op {
        using operation_state_concept = stdexec::operation_state_t;
        R rec_;

        void start() & noexcept { stdexec::set_value(std::move(rec_)); }
    };

    template <class Tag>
    Domain query(stdexec::get_completion_domain_t<Tag>,
                 auto&&...) const noexcept {
        return {};
    }

    struct env {
        template <class Tag>
        inline_scheduler query(
            stdexec::get_completion_scheduler_t<Tag>) const noexcept {
            return {};
        }
    };

    struct sender {
        using sender_concept = stdexec::sender_t;

        using completion_signatures =
            stdexec::completion_signatures<stdexec::set_value_t()>;

        template <stdexec::receiver_of<completion_signatures> R>
        op<R> connect(R rec) noexcept(std::is_nothrow_move_constructible_v<R>) {
            std::println("connect: {}", std::meta::display_string_of(^^R));
            return {std::move(rec)};
        }

        env get_env() const noexcept { return {}; }
    };

    inline_scheduler() = default;

    sender schedule() const noexcept { return {}; }

    bool operator==(const inline_scheduler&) const noexcept = default;
};

int main() {
    auto f = [] { std::println("foo"); };

    auto sch = inline_scheduler{};

    std::println("a");
    stdexec::sync_wait(sch.schedule());
    std::println();

    std::println("b");
    stdexec::sync_wait(sch.schedule() | stdexec::then(f));
    std::println();

    std::println("c");
    stdexec::sync_wait(stdexec::just() | stdexec::continues_on(sch) |
                       stdexec::then(f));
    std::println();

    std::println("d");
    stdexec::sync_wait(stdexec::just() | stdexec::on(sch, stdexec::then(f)));
    std::println();

    std::println("e");
    // stdexec::sync_wait(stdexec::starts_on(sch, stdexec::just()) | stdexec::then(f));
}

What I need to modify, in order to make the case e compile?