Update networkTypes.js

Author: ankianan

javascript/selenium-webdriver/bidi/networkTypes.js

@@ -119,6 +119,17 @@ class Header {
   get value() {
     return this._value
   }
+
+  /**
+   * Converts the Header to a map.
+   * @returns {Map<string, any>} A map representation of the Header.
+   */
+  asMap() {
+        return new Map([
+            ["name", this.name],
+            ["value", Object.fromEntries(this.value.asMap())]
+        ]);
+    };
 }
 
 /**