Remove utils/archive. It is not used at this point.

utils/archive/read_request.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/** The request ids for read-related messages to send to the C extension. */
-library read_request;
-
-final int NEW = 0;
-final int SUPPORT_FILTER_ALL = 1;
-final int SUPPORT_FILTER_BZIP2 = 2;
-final int SUPPORT_FILTER_COMPRESS = 3;
-final int SUPPORT_FILTER_GZIP = 4;
-final int SUPPORT_FILTER_LZMA = 5;
-final int SUPPORT_FILTER_XZ = 6;
-final int SUPPORT_FILTER_PROGRAM = 7;
-final int SUPPORT_FILTER_PROGRAM_SIGNATURE = 8;
-final int SUPPORT_FORMAT_ALL = 9;
-final int SUPPORT_FORMAT_AR = 10;
-final int SUPPORT_FORMAT_CPIO = 11;
-final int SUPPORT_FORMAT_EMPTY = 12;
-final int SUPPORT_FORMAT_ISO9660 = 13;
-final int SUPPORT_FORMAT_MTREE = 14;
-final int SUPPORT_FORMAT_RAW = 15;
-final int SUPPORT_FORMAT_TAR = 16;
-final int SUPPORT_FORMAT_ZIP = 17;
-final int SET_FILTER_OPTION = 18;
-final int SET_FORMAT_OPTION = 19;
-final int SET_OPTION = 20;
-final int OPEN_FILENAME = 21;
-final int OPEN_MEMORY = 22;
-final int NEXT_HEADER = 23;
-final int DATA_BLOCK = 24;
-final int DATA_SKIP = 25;
-final int CLOSE = 26;
-final int FREE = 27;
-
-final int LAST = FREE;