* IllegalStateException} if it is accessed in any way, with the following exceptions:
   *
   * <ul>
   *   <li>{@code view.equals(view)} evaluates to {@code true} (but any other `equals()` expression
   *       involving {@code view} will throw)
   *   <li>{@code hashCode()} does not throw
   *   <li>if {@code node} is re-added to the graph after having been removed, {@code view}'s
   *       behavior is undefined
   * </ul>
   *

     * <ul>
     * <li>{@code *} (since 2.0.5)= everything,</li>
     * <li>{@code external:*}  (since 2.0.9)= everything not on the localhost and not file based,</li>
     * <li>{@code external:http:*} (since 3.8.0)= any repository not on the localhost using HTTP,</li>
     * <li>{@code repo,repo1}  (since 2.0.9)= {@code repo} or {@code repo1},</li>

 *   <li>Convert multiple instances "forward" using {@code converter.convertAll(as)}.
 *   <li>Convert in the "backward" direction using {@code converter.reverse().convert(b)} or {@code
 *       converter.reverse().convertAll(bs)}.
 *   <li>Use {@code converter} or {@code converter.reverse()} anywhere a {@link
 *       java.util.function.Function} is accepted (for example {@link java.util.stream.Stream#map
 *       Stream.map}).

   *       fail.
   *   <li>If the constructor or factory method takes a parameter that {@link
   *       AbstractPackageSanityTests} doesn't know how to construct, the test will fail.
   *   <li>If there is no visible constructor or visible static factory method declared by {@code
   *       C}, {@code C} is skipped for serialization test, even if it implements {@link
   *       Serializable}.

     * </p>
     * <ul>
     *   <li>If this type is {@link JavaPathType#MODULES}, then this method returns
     *       {@code "--module-path path1:path2"} on Unix or {@code "--module-path path1;path2"} on Windows.</li>
     *   <li>If this type was created by {@code JavaPathType.patchModule("foo.bar")}, then the method returns

 * Benchmarks (as of December 2011) show that:
 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.
 *   <li>for nested locking, the cost increases with the depth of the nesting:
 *       <ul>
 *         <li>2 levels: average of 64ns per lock()/unlock()
 *         <li>3 levels: average of 77ns per lock()/unlock()

     * be able to accept <code>relative</code> parameter values that
     * <ul>
     * <li>use either / or \ file path separator,</li>
     * <li>have .. parent directory references,</li>
     * <li>point either at file or directory.</li>
     * </ul>
     *
     * @param relative is the path of the requested source relative to this source

 * second invocation, so implementors have made various choices, including:
 *
 * <ul>
 *   <li>returning the same iterator again
 *   <li>throwing an exception of some kind
 *   <li>or the usual, <i>robust</i> behavior, which all known {@link Collection} implementations
 *       have, of returning a new, independent iterator
 * </ul>
 *

 * </ul>
 *
 * <p>This class is similar to {@link MoreExecutors#newSequentialExecutor}. This class is different
 * in a few ways:
 *
 * <ul>
 *   <li>Each task may be associated with a different executor.
 *   <li>Tasks may be of type {@code AsyncCallable}.
 *   <li>Running tasks <i>cannot</i> be interrupted. (Note that {@code newSequentialExecutor} does

 *
 * <ul>
 *   <li>An annotation named just "Suppress" might someday be treated by a non-Android tool as a
 *       suppression. This would follow the precedent of many of our annotation processors, which
 *       look for any annotation named, e.g., "GwtIncompatible," regardless of package.
 *   <li>An annotation named just "Suppress" might suggest to users that the test is suppressed