Determine files count early from simple iterator

src/Runner/Runner.php

@@ -93,6 +93,7 @@ public function __construct(
  ?DirectoryInterface $directory = null
  ) {
  $this->runnerConfig = $runnerConfig;
+ $this->fileCount = \count($fileIterator ?? []); // Required only for main process (calculating workers count)
  $this->fileIterator = $fileIterator;
  $this->fixers = $fixers;
  $this->differ = $differ;
@@ -474,10 +475,6 @@ private function getFileIterator(): LintingResultAwareFileIteratorInterface
  : $this->fileIterator
  );
 
- // In order to determine the amount of required workers, we need to know how many files we need to analyse
- $this->fileCount = \count(iterator_to_array($fileIterator));
- $fileIterator->rewind(); // Important! Without this 0 files would be analysed
-
  $fileFilterIterator = new FileFilterIterator(
  $fileIterator,
  $this->eventDispatcher,