suspendtest.zig

const std = @import("std");

// outputs:
// from foo
// from bar

fn foo() void {
    suspend {
        _ = bar(@frame());
    }
    std.debug.warn("from foo\n");
}

fn bar(frame: anyframe) void {
    resume frame;
    std.debug.warn("from bar\n");
}

test "test" {
    _ = async foo();
}

    _ = async foo();
        _ = bar(@frame()); // tail call; bar() will return to foo's caller (test "test")
    resume frame;
    std.debug.warn("from foo\n"); // then return from foo() to bar()
    std.debug.warn("from bar\n"); // then return from bar() to test "test"