Manually starting a CaptureStream results in a single queued buffer

[isc-IAS]

I noticed a low FPS on my camera while using the crate, I think this may be the cause:
If .start() has not been called, calling the .next() method on an MMapStream queues all the buffers.
If .start() has been called it attempts to queue a single buffer.
Manually queuing the buffers at start can then cause an InvalidInput on the first call to .next() as it tries to re-queue the buffer.

Queues only a single buffer

let buffer_count = 4;
let v4l2_device = v4l::Device::with_path("/dev/video0").expect("failed to open video");
let mut stream = mmap::Stream::with_buffers(&v4l2_device, Type::VideoCapture, buffer_count)
    .expect("failed to create stream");
stream.start().expect("failed to start stream");

loop {
    let (_, meta) = stream.next().expect("failed to get image");
    println!("seq: {}, timestamp: {}", meta.sequence, meta.timestamp);
}

Fails with InvalidInput

let buffer_count = 4;
let v4l2_device = v4l::Device::with_path("/dev/video0").expect("failed to open video");
let mut stream = mmap::Stream::with_buffers(&v4l2_device, Type::VideoCapture, buffer_count)
    .expect("failed to create stream");

for index in 0..buffer_count as usize {
    stream.queue(index).expect("failed to queue buffer");
}
stream.start().expect("failed to start stream");

loop {
    let (_, meta) = stream.next().expect("failed to get image"); // <-- fails here
    println!("seq: {}, timestamp: {}", meta.sequence, meta.timestamp);
}

I believe creates expected behavior

let buffer_count = 4;
let v4l2_device = v4l::Device::with_path("/dev/video0").expect("failed to open video");
let mut stream = mmap::Stream::with_buffers(&v4l2_device, Type::VideoCapture, buffer_count)
    .expect("failed to create stream");

for index in 1..buffer_count as usize {
    stream.queue(index).expect("failed to queue buffer");
}
stream.start().expect("failed to start stream");

loop {
    let (_, meta) = stream.next().expect("failed to get image");
    println!("seq: {}, timestamp: {}", meta.sequence, meta.timestamp);
}

[apbr]

Thanks a lot for creating this issue. I also walked into this trap.
Your proposed fix worked for me as well.

To me the main issue seems to be that the public interface of the crate is not well structured/documented.

[SoZ0]

I second this
Was very confused on the performance difference was halving the expect fps of what my device is capable of.

for index in 1..buffer_count as usize {
    stream.queue(index).expect("failed to queue buffer");
}

was the exact fix i needed before starting the stream.

Thank you!