``` rust
#![no_std]
#![no_main]

// text    data     bss     dec     hex
//  280       0       0     280     118 without defmt_rtt
// 1064      56    1032    2152     868 with defmt_rtt
use defmt_rtt as _;

#[cortex_m_rt::entry]
fn main() -> ! {
    loop {}
}

#[panic_handler]
fn panic(_: &core::panic::PanicInfo) -> ! {
    cortex_m::asm::udf();
}
```

Is this the expected overhead of RTT on a cortex-m0?
~800b code size increase feels like a lot for cobs encoding into a ring buffer