BlueScreen: renderToFile() returns bool to indicate if file was writt…

…en by current process (#325)

src/Tracy/BlueScreen.php

@@ -89,7 +89,7 @@ public function render(\Throwable $exception): void
 	/**
 	 * Renders blue screen to file (if file exists, it will not be overwritten).
 	 */
-	public function renderToFile(\Throwable $exception, string $file): void
+	public function renderToFile(\Throwable $exception, string $file): bool
 	{
 		if ($handle = @fopen($file, 'x')) {
 			ob_start(); // double buffer prevents sending HTTP headers in some PHP
@@ -98,7 +98,9 @@ public function renderToFile(\Throwable $exception, string $file): void
 			ob_end_flush();
 			ob_end_clean();
 			fclose($handle);
+			return true;
 		}
+		return false;
 	}