src/Authentication/Adapter/DefaultAdapter.php
public function preprocessCredential($credential)
    {
        $processor = $this->getCredentialPreprocessor();
        if (is_callable($processor)) {
            return $processor($credential);
        }

        return $credential;
    }
public function preprocessCredential($credential)
    {
        $processor = $this->getCredentialPreprocessor();
        if (is_callable($processor)) {
            return $processor($credential);
        }

        return $credential;
    }
Preprocess credential

@param string $credential
@return string