dirbaio[m]: > <@dirbaio:matrix.org> > It was originally done based on an incorrect assumption
> 
> there were a few motivations originally
> - impls may need mutable state
> - impls may need exclusive access to some underlying thing)
>    - out of these, "exclusive access to an i2c/spi bus for a GPIO expander" turned out to be an incorrect assumption, yes, because these likely have multiple pins so RefCell is needed anyway. The rest of motivations are still valid IMO.

but impls that need mutable state or exclusive access can still use some sort of interior mutability, right? and we expect the majority of impls don't?