*
 * <p>{@code ByteSink} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a stream:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned stream is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

     * get the type of toolchain.
     *
     * @return the toolchain type
     */
    String getType();

    /**
     * Gets the platform tool executable.
     *
     * @param toolName the tool platform independent tool name
     * @return file representing the tool executable, or null if the tool cannot be found
     */
    String findTool(String toolName);

    /**

 *
 * <p>{@code CharSource} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a reader:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned reader is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

                }
            }
        }

        return s;
    }

    /**
     * Removes the leading directory separator from the specified filesystem path (if any). For platform-independent
     * behavior, this method accepts both the forward slash and the backward slash as separator.
     *
     * @param path The filesystem path, may be <code>null</code>.

 * immutable <i>supplier</i> of {@code InputStream} instances.
 *
 * <p>{@code ByteSource} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a stream:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned stream is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

   *       correctly, including surrogate character pairs. If the input is badly formed the escaper
   *       should throw {@link IllegalArgumentException}.
   *   <li>{@link CharEscaper} handles Java characters independently and does not verify the input
   *       for well formed characters. A {@code CharEscaper} should not be used in situations where
   *       input is not guaranteed to be restricted to the Basic Multilingual Plane (BMP).

     */
    private static final String GROUP_ID = "unittest";
    private static final String PARENT_MODULE = "module-parent";
    private static final String INDEPENDENT_MODULE = "module-independent";
    private static final String MODULE_A = "module-a";
    private static final String MODULE_B = "module-b";
    private static final String MODULE_C = "module-c";
    private static final String MODULE_D = "module-d";

import java.util.Iterator;
import java.util.List;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A collection that supports order-independent equality, like {@link Set}, but may have duplicate
 * elements. A multiset is also sometimes called a <i>bag</i>.
 *
 * <p>Elements of a multiset that are equal to one another are referred to as <i>occurrences</i> of

 *       fulfills the {@link java.util.List} contract.
 *   <dt>{@link SetMultimap}
 *   <dd>An extension of {@link Multimap} which has order-independent equality and does not allow
 *       duplicate entries; that is, while a key may appear twice in a {@code SetMultimap}, each
 *       must map to a different value. {@code SetMultimap} takes its name from the fact that the

   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this
  static final int DRAIN_MAX = 16;

  // Fields

  /**