AugustoRoman[m]: Simplified Code is:
```
// Using Mutex/Option wrapper as suggested by https://embassy.dev/book/dev/sharing_peripherals.html#_sharing_using_a_mutex
static HUB75: Mutex<CriticalSectionRawMutex, Option<Hub75<'static, PIO1>>> = Mutex::new(None);
static DISPLAY: TripleBuffer = TripleBuffer::new();
...
#[cortex_m_rt::entry]
fn main() -> ! {
  ...
  let hub75 = Hub75::new(...);
  { HUB75.try_lock().unwrap().replace(hub75); }
  ... // spawn core0_display and others
}

#[embassy_executor::task]
async fn core0_display() {
  let mut hub75_lock = HUB75.lock().await;
  let hub75 = hub75_lock.as_mut().unwrap();
  loop {
    DISPLAY.view(|display| async {                     // ERROR IS HERE
      hub75.draw_frame(0, &display.buffer).await;      // hub75 lasts forever,
      hub75.draw_frame(1, &display.buffer).await;      // display is temporary.
    }).await;                                          // Should be OK?
  }
}

...

impl Hub75<'static, PIO> {
  pub async fn draw_frame(&mut self, bit: usize, frame: &[u32; 64 * 32]) { ... }
}

...

pub struct TripleBuffer {
  buffers: [Mutex<CriticalSectionRawMutex, FrameBuffer>; 3],
  readable: Mutex<CriticalSectionRawMutex, ReadableContainer>,
  spare: Mutex<CriticalSectionRawMutex, SpareContainer>,
  writeable: Mutex<CriticalSectionRawMutex, WriteableContainer>,
}
pub struct FrameBuffer { pub buffer: [u32; (WIDTH*HEIGHT) as usize] }
struct ReadableContainer { buffer_idx: usize }
struct SpareContainer { buffer_idx: usize, is_published: bool }
struct WriteableContainer { buffer_idx: usize, is_dirty: bool }

impl TripleBuffer {
  pub const fn new() -> Self { ... }
  pub async fn view<F, Fut>(&self, op: F)
    where
      F: FnOnce(&FrameBuffer) -> Fut,
      Fut: Future<Output = ()>,
  {
    let mut rc = self.readable.lock().await;
    {
      let mut spare = self.spare.lock().await;
      if spare.is_published {
        swap(&mut spare.buffer_idx, &mut rc.buffer_idx);
      }
    }
    let buf = &self.buffers[rc.buffer_idx].lock().await;
    op(&buf).await;
    _ = rc; // does this matter? make sure it's still alive, but probably doesn't matter.
  }
  ...
}
```