/**
* @inheritDoc
*/
public function peek($index = 0, $limit = 20)
{
$it = new \InfiniteIterator(new \ArrayIterator($this->queues));
$envelopes = $drained = $indexes = [];
foreach (array_keys($this->queues) as $name) {
$indexes[$name] = 0;
}
$shift = 0;
$key = key($this->queues);
for ($it->rewind(); $it->key() != $key; $it->next()) {
// noop
}
while (count($envelopes) < $limit && count($drained) < $it->count()) {
$queue = $it->current();
$name = $it->key();
if ($peeked = $queue->peek($indexes[$name], 1)) {
if ($shift < $index) {
$shift++;
$indexes[$name]++;
} else {
$envelopes[] = array_shift($peeked);
}
} else {
$drained[$name] = true;
}
$it->next();
}
return $envelopes;
}
