convert encryption type to enhanced enum

 /// Wifi encryption type constants.
 enum EncryptionType {
   /// Unknown encryption type.
-  ///
-  /// Constant Value: 0
-  none,
+  none(0),
 
   /// Not encrypted.
-  ///
-  /// Constant Value: 1
-  open,
+  open(1),
 
   /// WPA level encryption.
-  ///
-  /// Constant Value: 2
-  wpa,
+  wpa(2),
 
   /// WEP level encryption.
-  ///
-  /// Constant Value: 3
-  wep,
+  wep(3);
+
+  const EncryptionType(this.rawValue);
+
+  factory EncryptionType.fromRawValue(int value) {
+    switch (value) {
+      case 1:
+        return EncryptionType.open;
+      case 2:
+        return EncryptionType.wpa;
+      case 3:
+        return EncryptionType.wep;
+      case 0:
+      default:
+        return EncryptionType.none;
+    }
+  }
+
+  /// The raw value for the encryption type.
+  final int rawValue;
 }