Macro impl_opaque_ref_counted_facade 

macro_rules! impl_opaque_ref_counted_facade {
    (
        $(#[$meta:meta])*
        $vis:vis struct $name:ident,
        $recycle_fn:path $(,)?
    ) => { ... };
    (
        $(#[$meta:meta])*
        $vis:vis struct $name:ident,
        $recycle_fn:path,
        $get_ref_counted_fn:path $(,)?
    ) => { ... };
}

Declares a zero-sized facade struct for an opaque refcounted C++ object and implements HasRefCount and Recyclable for it.

Supported forms:

1. Where fbl::RefCounted is at offset 0 of the C++ object:

fbl::impl_opaque_ref_counted_facade!(
    /// Facade type representing the C++ `iommu::Iommu` object.
    pub struct Iommu,
    cpp_iommu_recycle,
);

2. Where fbl::RefCounted is at a non-zero offset or requires a C++ helper function:

fbl::impl_opaque_ref_counted_facade!(
    /// Facade type representing the C++ `VmObject` object.
    pub struct VmObject,
    cpp_vm_object_free,
    cpp_vm_object_get_ref_counted,
);