Creates `reflectors`, as a meta-meta feature that enables dynamic selection of a "mirror system".

reflectable/lib/src/encoding_constants.dart

 // Copyright (c) 2015, the Dart Team. All rights reserved. Use of this
 // source code is governed by a BSD-style license that can be found in
 // the LICENSE file.
 
 library reflectable.encoding_constants;
 
 // The first `flagsBit-1` bits are used to enumerate the "kind" of the
 // declaration. The more significant bits are flags.
 const flagsBit = 4;
 
 // Kinds:
 const generativeConstructor = 0;
 const factoryConstructor = 1;
 const method = 2;
 const getter = 3;
 const setter = 4;
 const field = 5;
 const parameter = 6;
+const clazz = 7; // Cannot use keyword `class`.
 
 // Flags:
 const staticAttribute = 1 << (flagsBit);
 const privateAttribute = 1 << (flagsBit + 1);
 const syntheticAttribute = 1 << (flagsBit + 2);
 const constAttribute = 1 << (flagsBit + 3);
 const redirectingConstructorAttribute = 1 << (flagsBit + 4);
 const abstractAttribute = 1 << (flagsBit + 5);
 const finalAttribute = 1 << (flagsBit + 6);
 const hasDefaultValueAttribute = 1 << (flagsBit + 7);
 const optionalAttribute = 1 << (flagsBit + 8);
 const namedAttribute = 1 << (flagsBit + 9);
 const dynamicAttribute = 1 << (flagsBit + 10);
 const classTypeAttribute = 1 << (flagsBit + 11);
 const dynamicReturnTypeAttribute = 1 << (flagsBit + 12);
 const classReturnTypeAttribute = 1 << (flagsBit + 13);
 const voidReturnTypeAttribute = 1 << (flagsBit + 14);
+const enumAttribute = 1 << (flagsBit + 15);
 
 int kindFromEncoding(int encoding) => encoding & ((1 << flagsBit) - 1);
 
 /// Used in place of an index into a list, where a needed capability to provide
 /// the actual value is missing.
 const int NO_CAPABILITY_INDEX = -1;