Struct Prefixed 

pub struct Prefixed<'a, R>
where
    R: RangeReader + ?Sized,
{
    pub first: &'a [u8],
    pub r: &'a R,
}

A borrowed reader whose first bytes are already in memory: reads inside them cost nothing, the rest go to r.

Fields

first: &'a [u8]

The file’s first bytes.

r: &'a R

The reader behind them.

Trait Implementations

impl<R> RangeReader for Prefixed<'_, R>

where R: RangeReader + ?Sized,

fn len(&self) -> u64

Total resource length in bytes.

fn read_at(&self, offset: u64, len: u64) -> Result<Vec<u8>, Error>

Read len bytes starting at offset. Implementations should error on an out-of-bounds range rather than truncating.

fn is_empty(&self) -> bool

True when the resource is empty.

fn read_many(&self, ranges: &[(u64, u64)]) -> Result<Vec<Vec<u8>>, Error>

Read several (offset, len) ranges, returning each range’s bytes in request order. These ranges are independent, so a reader whose backing store is high-latency but parallelizable (an HTTP client) overrides this to issue the reads concurrently — turning N round trips into ~N/P. The default fetches them sequentially. Any range failing fails the batch.

fn concurrency(&self) -> usize

How many ranges this reader can usefully have in flight at once — the planner’s hint for probe-vs-scan and batch-size decisions (a phone’s serial sync-XHR reader reports 1; the CLI’s threaded HTTP client and the browser’s concurrent-fetch variants report their fan-out). Purely advisory: correctness never depends on it. Defaults to 1 (sequential).