Fixed headers error from new line in Server Timing.

Fixes #28

CHANGELOG.md

@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+### Fixed
+- headers error from new line in Server Timing
+
 ## 3.0.1 - 2019-01-09
 
 ### Fixed

src/Manager/Server_Timing_Manager.php

@@ -64,7 +64,7 @@ class Server_Timing_Manager {
 			$header .= sprintf( '%s;dur=%.2f;desc="%s", ', $record->get_category(), $duration, $record->get_name() );
 		}
 
-		header( 'Server-Timing: ' . $header );
+		header( 'Server-Timing: ' . preg_replace( '/\R/', '', $header ) );
 
 		return $input;
 	}