Type Alias RangeExtractor 

pub type RangeExtractor = Arc<dyn Fn(Range, &mut dyn FnMut(usize)) + Send + Sync>;

A callback that emits virtual item indexes for a given visible range.

This is designed for zero-allocation adapters: instead of returning a Vec, the extractor receives an emit callback and can push indexes directly into the adapter’s output buffer.

Contract:

• emit(i) must be called with i < range.count.
• The emitted indexes must be sorted ascending; duplicates are allowed but ignored.

Tip: use crate::IndexEmitter to enforce the contract (and to avoid accidental panics in debug builds).

Aliased Type

pub struct RangeExtractor { /* private fields */ }