A robust and optimized library for advanced PHP Iterators.

Transformation and inspection

Class	Purpose	Important notes
`ClosureIteratorIterator`	applies a closure to every visible value	the closure receives both value and key
`TrimIteratorIterator`	trims strings lazily during iteration	built on top of `ClosureIteratorIterator`
`UniqueIteratorIterator`	returns only first occurrences	key positions are normalized and options control strictness and case handling
`LookaheadIterator`	lets you inspect upcoming or previous values	`lookAhead()` and `lookBehind()` never advance the main iterator
`RangeIterator`	lazily generates integer or floating-point ranges	can force the final boundary when a step would overshoot it
`FileExtensionFilterIterator`	filters filesystem entries by extension	recursive iterators are traversed recursively before filtering

Class	Purpose	Important notes
`ChunkedIteratorAggregate`	splits a source into fixed-size chunks	the last chunk can be shorter
`SlidingWindowIteratorIterator`	yields overlapping windows	produces no output if the source is shorter than the requested window
`ConsecutiveGroupIterator`	groups adjacent values while a callback keeps returning `true`	useful for runs, streaks, and boundary detection
`GroupByIteratorIterator`	groups the whole dataset by a computed key	rewinding recomputes the full grouped structure

Class	Purpose	Important notes
`ChainIterableIterator`	appends several iterables one after another	numeric keys are normalized to sequential positions
`InterleaveIteratorIterator`	alternates between sources in round-robin order	continues until all sources are exhausted
`ZipIteratorIterator`	aligns sources side by side into tuples	stops at the shortest input
`RepeatableIteratorIterator`	cycles through a source for a fixed number of reads	excellent for controlled repetition with a limit
`GeneratorRewindableIterator`	makes a generator reusable across loops	wraps cached generator output behind a direct iterator API
`GeneratorCachingIteratorAggregate`	exposes a cached aggregate view of a generator	useful when repeated iteration should still feel like an aggregate

ChunkedIteratorAggregate and SlidingWindowIteratorIterator both return arrays, but only sliding windows overlap.
ConsecutiveGroupIterator groups neighbors, while GroupByIteratorIterator groups by computed bucket across the entire input.
ChainIterableIterator , InterleaveIteratorIterator , and ZipIteratorIterator all combine sources, but they model append, round-robin, and lockstep behavior respectively.
GeneratorRewindableIterator and GeneratorCachingIteratorAggregate both support repeated generator iteration; choose the one that best fits whether your API wants an iterator or an aggregate.