You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: qspi.rs
    path of file: ./repos/embassy/examples/nrf52840/src/bin
    
    the code of the file until where you have to start completion: #![no_std]
#![no_main]

use defmt::{assert_eq, info, unwrap};
use embassy_executor::Spawner;
use embassy_nrf::qspi::Frequency;
use embassy_nrf::{bind_interrupts, peripherals, qspi};
use {defmt_rtt as _, panic_probe as _};

const PAGE_SIZE: usize = 4096;

// Workaround for alignment requirements.
// Nicer API will probably come in the future.
#[repr(C, align(4))]
struct AlignedBuf([u8; 4096]);

bind_interrupts!(struct Irqs {
    QSPI => qspi::InterruptHandler<peripherals::QSPI>;
});

#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let p = embassy_nrf::init(Default::default());
    // Config for the MX25R64 present in the nRF52840 DK
    let mut config = qspi::Config::default();
    config.capacity = 8 * 1024 * 1024; // 8 MB
    config.frequency = Frequency::M32;
    config.read_opcode = qspi::ReadOpcode::READ4IO;
    config.write_opcode = qspi::WriteOpcode::PP4IO;
    config.write_page_size = qspi::WritePageSize::_256BYTES;

    let mut q = qspi::Qspi::new(
        p.QSPI, Irqs, p.P0_19, p.P0_17, p.P0_20, p.P0_21, p.P0_22, p.P0_23, config,
    );

    let mut id = [1; 3];
    unwrap!(q.custom_instruction(0x9F, &[], &mut id).await);
    info!("id: {}", id);

    // Read status register
    let mut status = [4; 1];
    unwrap!(q.custom_instruction(0x05, &[], &mut status).await);

    info!("status: {:?}", status[0]);

    if status[0] & 0x40 == 0 {
        status[0] |= 0x40;

        unwrap!(q.custom_instruction(0x01, &status, &mut []).await);

        info!("enabled quad in status");
    }

    let mut
    
async fn main(_spawner: Spawner) {
    let p = embassy_nrf::init(Default::default());
    // Config for the MX25R64 present in the nRF52840 DK
    let mut config = qspi::Config::default();
    config.capacity = 8 * 1024 * 1024; // 8 MB
    config.frequency = Frequency::M32;
    config.read_opcode = qspi::ReadOpcode::READ4IO;
    config.write_opcode = qspi::WriteOpcode::PP4IO;
    config.write_page_size = qspi::WritePageSize::_256BYTES;

    let mut q = qspi::Qspi::new(
        p.QSPI, Irqs, p.P0_19, p.P0_17, p.P0_20, p.P0_21, p.P0_22, p.P0_23, config,
    );

    let mut id = [1; 3];
    unwrap!(q.custom_instruction(0x9F, &[], &mut id).await);
    info!("id: {}", id);

    // Read status register
    let mut status = [4; 1];
    unwrap!(q.custom_instruction(0x05, &[], &mut status).await);

    info!("status: {:?}", status[0]);

    if status[0] & 0x40 == 0 {
        status[0] |= 0x40;

        unwrap!(q.custom_instruction(0x01, &status, &mut []).await);

        info!("enabled quad in status");
    }

    let mut buf = AlignedBuf([0u8; PAGE_SIZE]);

    let pattern = |a: u32| (a ^ (a >> 8) ^ (a >> 16) ^ (a >> 24)) as u8;

    for i in 0..8 {
        info!("page {:?}: erasing... ", i);
        unwrap!(q.erase(i * PAGE_SIZE as u32).await);

        for j in 0..PAGE_SIZE {
            buf.0[j] = pattern((j as u32 + i * PAGE_SIZE as u32) as u32);
        }

        info!("programming...");
        unwrap!(q.write(i * PAGE_SIZE as u32, &buf.0).await);
    }

    for i in 0..8 {
        info!("page {:?}: reading... ", i);
        unwrap!(q.read(i * PAGE_SIZE as u32, &mut buf.0).await);

        info!("verifying...");
        for j in 0..PAGE_SIZE {
            assert_eq!(buf.0[j], pattern((j as u32 + i * PAGE_SIZE as u32) as u32));
        }
    }

    info!("done!")
}