Assign any event kind to a single templatized function ?

[Basile B. via Digitalmars-d-learn]

It's almost a "yeah". However this doesn't work with ref 
parameters. Any idea how to make this work, keeping the 
simplicity of the concept ?

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module runnable;
import std.stdio;

struct Foo
{
    void delegate(int) event1;
    void delegate(int,int) event2;
    void delegate(int,ref int) event3;
}

struct Handler
{
    void handle(A...)(A a){writeln(a);}
    void handleref(A...)(/*auto ref*/ A a){writeln(a);}
}

void main(string[] args)
{
    import std.traits;
    Foo foo;
    Handler handler;
    foo.event1 = &handler.handle!(Parameters!(foo.event1));
    foo.event2 = &handler.handle!(Parameters!(foo.event2));
    foo.event3 = &handler.handleref!(Parameters!(foo.event2)); // 
?
}
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