coroutine.php

<?php

class DataProvider
{
    public function execute(): \Generator
    {
        while(true) {
            $requests = yield;
            foreach ($requests as $request) {
                yield $request . ' - appended';
            }
        }
    }
}

class DataRequester
{
    /** @var DataProvider */
    private $dataProvider;

    public function __construct(DataProvider $dataProvider)
    {
        $this->dataProvider = $dataProvider;
    }

    public function execute(array $batches): void
    {
        $coroutine = $this->dataProvider->execute();
        foreach ($batches as $batch) {
            while($result = $coroutine->send($batch)) {
                echo $result . "\n";
            }
        }
    }
}

$requester = new DataRequester(
    new DataProvider()
);
$requester->execute([['a','b','c'],['d','e','f'],['g','h','i']]);


/*

Results in:

a - appended
b - appended
c - appended
d - appended
e - appended
f - appended
g - appended
h - appended
i - appended
*/