Add String extensions

Author: colemancda

Sources/HTTP/Extensions/String.swift

@@ -0,0 +1,15 @@
+//
+//  String.swift
+//  HTTP
+//
+//  Created by Alsey Coleman Miller on 10/1/25.
+//
+
+import Foundation
+
+internal extension String {
+    
+    var isASCII: Bool {
+        self.utf8.allSatisfy { $0 & 0x80 == 0 }
+    }
+}