This is in my main loop to handle the adc dma. Does this seem reasonable for continual sampling?
```rust
        if transfer.is_done() {
            let (buf, adc_dma) = transfer.wait();

            // Read buf here

            transfer = adc_dma.read(buf);
        }
```

Setup is:
```rust
    let dma_ch1 = dp.DMA1.split().1;
    let adc1 = Adc::adc1(dp.ADC1, clocks);
    let pin_adc_0 = gpioa.pa0.into_analog(&mut gpioa.crl);
    let adc_dma = adc1.with_dma(pin_adc_0, dma_ch1);
    let mut transfer = unsafe { adc_dma.read(&mut BUF) };
```