Struct Config 

pub struct Config {

    pub threads: usize,
    pub proxy: Proxy<String>,
    pub headers: HashMap<String, String>,
    pub min_chunk_size: u64,
    pub sync_all: bool,
    pub write_buffer_size: usize,
    pub cache_high_watermark: usize,
    pub cache_low_watermark: usize,
    pub write_queue_cap: usize,
    pub retry_gap: Duration,
    pub pull_timeout: Duration,
    pub accept_invalid_certs: bool,
    pub accept_invalid_hostnames: bool,
    pub retry_times: usize,
    pub local_address: Vec<IpAddr>,
    pub max_speculative: usize,
    pub downloaded_chunk: Arc<Mutex<Vec<ProgressEntry>>>,
    pub chunk_window: u64,
}

Fields

threads: usize

Number of threads. Recommended: 32 / 16 / 8. More threads does not always mean faster.

proxy: Proxy<String>

Proxy setting. Supports https, http, and socks5 proxies.

headers: HashMap<String, String>

Custom request headers.

min_chunk_size: u64

Minimum chunk size in bytes. Recommended: 8 * 1024 * 1024

• Chunks that are too small may cause heavy contention.
• When chunking is no longer possible, speculative mode is used.

sync_all: bool

Whether to ensure data is fully flushed to disk. Recommended: false

Set to true only if you need to power off immediately after download.

write_buffer_size: usize

Write buffer size in bytes. Recommended: 16 * 1024 * 1024

• Only effective for WriteMethod::Std. Helps convert random writes into sequential writes.
• Not used for WriteMethod::Mmap, as the buffer is managed by the OS.

cache_high_watermark: usize

Cache high watermark in bytes. Recommended: 16 * 1024 * 1024

When the byte merge buffer reaches this size, a merge flush is triggered to reduce the buffer to cache_low_watermark or below.

• Only effective for WriteMethod::Std.
• Not used for WriteMethod::Mmap.

cache_low_watermark: usize

Cache low watermark in bytes. Recommended: 8 * 1024 * 1024

After a merge flush, the byte merge buffer size is reduced to this level or below.

• Only effective for WriteMethod::Std.
• Not used for WriteMethod::Mmap.

write_queue_cap: usize

Write queue capacity. Recommended: 10240

If download threads fill the write queue, backpressure is applied to slow down downloads and prevent excessive memory usage.

retry_gap: Duration

Default retry interval after a request failure. Recommended: 500ms

If the server returns a Retry-After header, that value takes precedence.

pull_timeout: Duration

Pull timeout. Recommended: 5000ms

If no bytes are received within pull_timeout after sending the request, the connection is dropped and re-established. This helps TCP detect congestion and can improve download speed.

accept_invalid_certs: bool

Whether to accept invalid certificates (dangerous). Recommended: false

accept_invalid_hostnames: bool

Whether to accept invalid hostnames (dangerous). Recommended: false

retry_times: usize

Number of retries for fetching metadata. Recommended: 10. Note: this is not the retry count during download.

local_address: Vec<IpAddr>

Local IP addresses to bind for outgoing requests. Recommended: Vec::new()

If you have multiple network interfaces, you can provide their IP addresses; requests will be rotated among them. This may not always improve speed.

max_speculative: usize

Maximum number of speculative workers. Recommended: 3

When the remaining chunk is smaller than min_chunk_size and cannot be split, speculative mode is used. Up to max_speculative workers compete on the same chunk to prevent the download from stalling near 99%.

downloaded_chunk: Arc<Mutex<Vec<ProgressEntry>>>

Already downloaded chunks. Pass Vec::new() to download the entire file.

chunk_window: u64

Smoothing window for downloaded chunks in bytes. Recommended: 8 * 1024

Filters out small gaps in downloaded_chunk that are smaller than chunk_window to reduce the number of HTTP requests.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Config

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.