src/Protocol/Http/Request.php
public function withCertificatePassPhrase(string $passPhrase): Request
    {
        $cloned = clone $this;

        $cloned->certificatePassPhrase = $passPhrase;

        return $cloned;
    }
public function withCertificatePassPhrase(string $passPhrase): Request
    {
        $cloned = clone $this;

        $cloned->certificatePassPhrase = $passPhrase;

        return $cloned;
    }
Use pass phrase of certificate for send request

@param string $passPhrase

@return Request