Correct type for storing a relaod_handle in a struct

[akanalytics]

Im trying to hold a reload_handle for a FmtSubscriber in a struct so I can later use the reload/modify methods to change level.
Because Im using stderr (my program uses stdout for its output), the type Handle<EnvFilter, Formatter> doesnt seem to work.
Ideally I'd just like to Box the reload_handle, as reloading is not a performance critical part, and it would remove excessive genrics from MyStruct.

struct MyStruct {
handle: WhatTypeHere,
}

let builder = FmtSubscriber::builder()
.with_writer(io::stderr)
.with_env_filter(EnvFilter::from_default_env())
.with_filter_reloading();

let reload_handle = builder.reload_handle();

let my_struct = MyStruct {
handle: reload_handle,
}