class RawMessage

class RawMessage {
    private bool $isGeneratorClosed;
    
    /**
     * @param iterable<string>|string|resource $message
     */
    public function __construct($message) {
    }
    public function __destruct() {
        if (\is_resource($this->message)) {
            fclose($this->message);
        }
    }
    public function toString() : string {
        if (\is_string($this->message)) {
            return $this->message;
        }
        if (\is_resource($this->message)) {
            return stream_get_contents($this->message, -1, 0);
        }
        $message = '';
        foreach ($this->message as $chunk) {
            $message .= $chunk;
        }
        return $this->message = $message;
    }
    public function toIterable() : iterable {
        if ($this->isGeneratorClosed ?? false) {
            throw new LogicException('Unable to send the email as its generator is already closed.');
        }
        if (\is_string($this->message)) {
            (yield $this->message);
            return;
        }
        if (\is_resource($this->message)) {
            rewind($this->message);
            while ($line = fgets($this->message)) {
                (yield $line);
            }
            return;
        }
        if ($this->message instanceof \Generator) {
            $message = fopen('php://temp', 'w+');
            foreach ($this->message as $chunk) {
                fwrite($message, $chunk);
                (yield $chunk);
            }
            $this->isGeneratorClosed = !$this->message
                ->valid();
            $this->message = $message;
            return;
        }
        foreach ($this->message as $chunk) {
            (yield $chunk);
        }
    }
    
    /**
     * @throws LogicException if the message is not valid
     */
    public function ensureValidity() : void {
    }
    public function __serialize() : array {
        return [
            $this->toString(),
        ];
    }
    public function __unserialize(array $data) : void {
        [
            $this->message,
        ] = $data;
    }

}