Why isn't it printing the line?

[sasr22]

I am trying to implement the org.bluez.Profile1 interface like this:

use dbus::{
    arg::PropMap,
    blocking::Connection,
};
use dbus_crossroads::{Context, Crossroads};
use std::{error::Error, fs::File, io::{Write, Read}};

struct Profile {}

fn main() -> Result<(), Box<dyn Error>> {
    let c = Connection::new_system()?;
    c.request_name("org.example.Profile1", false, true, false)?;
    let mut cr = Crossroads::new();

    let iface_token = cr.register("org.bluez.Profile1", |b| {
        b.method(
            "NewConnection",
            ("device", "fd", "fd_properties"),
            (),
            move |ctx: &mut Context,
                  profile: &mut Profile,
                  (device, mut fd, fd_properties): (dbus::Path, File, PropMap)| {
                println!("Incoming connection! {}", device);
                Ok(())
            },
        );

        b.method(
            "RequestDisconnection",
            ("device",),
            (),
            move |ctx: &mut Context, profile: &mut Profile, (device,): (dbus::Path,)| {
                println!("Incoming disconnection! {}", device);
                Ok(())
            },
        );

        b.method(
            "Release",
            (),
            (),
            move |ctx: &mut Context, profile: &mut Profile, (): ()| {
                println!("Incoming release!");
                Ok(())
            },
        );
    });

    cr.insert("/org/example/profile", &[iface_token], Profile {});

    cr.serve(&c)?;
    unreachable!()
}

After registering it like this:

use dbus::{arg::Variant, blocking::Connection};
use std::{collections::HashMap, time::Duration, fs::File, io::Read};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let conn = Connection::new_system()?;

    let proxy_profile_manager =
        conn.with_proxy("org.bluez", "/org/bluez", Duration::from_millis(5000));

    let mut opts = HashMap::new();

    opts.insert("name", Variant("HFP"));

    let path = dbus::Path::from("/org/example/profile");

    proxy_profile_manager.method_call(
        "org.bluez.ProfileManager1",
        "RegisterProfile",
        (path, "hfp-hf", opts),
    )?;

    loop {}
}

The print lines do not work, but it is being called as i see this line in dbus-monitor:

method call time=1694959546.590652 sender=:1.283 -> destination=:1.336 serial=454 path=/org/example/profile; interface=org.bluez.Profile1; member=NewConnection
   object path "/org/bluez/hci0/dev_XX_XX_XX_XX_XX_XX"
   file descriptor
         inode: 106847
         type: socket
         address family: bluetooth
   array [
      dict entry(
         string "Version"
         variant             uint16 263
      )
      dict entry(
         string "Features"
         variant             uint16 47
      )
   ]

[diwic]

I'm not sure, but maybe the problem is that you're using two separate connections? The method call is sent to destination=:1.336, not destination=org.example.Profile1.

What if you used the same connection to register the profile and then to listen to the incoming method calls?