Function gen_opaque_struct_prefixed 

pub fn gen_opaque_struct_prefixed(
    typ: &TypeDef,
    cfg: &RustBindingConfig<'_>,
    prefix: &str,
) -> String

Generate an opaque wrapper struct with inner: Arc<core::Type> and a name prefix. For types with &mut self methods, uses Arc<Mutex<core::Type>>.

Special case: if ALL methods on this type are sanitized, omit the inner field. See gen_opaque_struct for the rationale.