Filesystem/CsvResource.php
public function rewind(): void
    {
        $this->assertOpened();
        if (!rewind($this->handler)) {
            throw new \RuntimeException("Unable to rewind '{$this->getResourceName()}'");
        }
        $this->currentLine = 0;
        if (!$this->manualHeaders) {
            $this->readRaw(); // skip headers
        }
    }
public function rewind(): void
    {
        $this->assertOpened();
        if (!rewind($this->handler)) {
            throw new \RuntimeException("Unable to rewind '{$this->getResourceName()}'");
        }
        $this->currentLine = 0;
        if (!$this->manualHeaders) {
            $this->readRaw(); // skip headers
        }
    }
This methods rewinds the file to the first line of data, skipping the headers.

@throws \RuntimeException