Wrappers

This is not a flutter_rust_bridge feature, but an approach that can be useful here, and is discussed for completeness.

Example

Suppose in third party crate there is a type:

pub struct Foo { .. }

impl Foo {
    pub fn method_one(..) -> .. { .. }
    pub fn method_two(..) -> .. { .. }
    ...
}

And suppose it has some special fields making it not Sync, thus cannot directly be used. For simplicity, let us wrap it using a Mutex:

pub struct Foo(Mutex<third_party_crate::Foo>);

Then, how can we expose the methods? We can surely write down each and every one manually:

// Naive approach, do NOT use
impl Foo {
    pub fn method_one(..) -> .. {
        self.0.lock().unwrap().method_one(..)
    }
    pub fn method_two(..) -> .. {
        self.0.lock().unwrap().method_two(..)
    }
    ...
}

But that's tedious. We can do it faster by using delegate-attr or something liek that. Essentially, it does nothing but helping us generate those method bodies. Then the code looks like:

#[delegate(self.0.lock().unwrap())] // <-- just add this, and leave the method body empty
impl Foo {
    pub fn method_one(..) -> .. {}
    pub fn method_two(..) -> .. {}
    ...
}