<RobinMueller[m]> "Does anyone have experience with..." <- bisync is great. You can deal with embedded_hal vs embedded_hal_async traits by importing the symbols into the module, then inside the implementation modules, use relative paths like `super::SpiBus` rather than `crate::SpiBus` or `embedded_hal::spi::SpiBus`. For example, in embedded-sdmmc's lib.rs I have:

```rust
/// Blocking implementation of this crate. Uses traits from embedded_hal & embedded_io crates.
#[path = "."]
pub mod blocking {
    use bisync::synchronous::*;
    use embedded_hal::{delay::DelayNs, spi::SpiDevice};
    use embedded_io::{ErrorType, Read, Seek, SeekFrom, Write};
    mod inner;
    pub use inner::*;
}

/// Async implementation of this crate. Uses traits from embedded_hal_async & embedded_io_async crates.
#[path = "."]
pub mod asynchronous {
    use bisync::asynchronous::*;
    use embedded_hal_async::{delay::DelayNs, spi::SpiDevice};
    use embedded_io_async::{ErrorType, Read, Seek, SeekFrom, Write};
    mod inner;
    pub use inner::*;
}
```