*
     * @param css the CSS class name to match
     */
    public void setCss(final String css) {
        this.css = css;
    }

    /**
     * Sets a custom attribute name-value pair that this pruned tag should match.
     *
     * @param name the attribute name to match
     * @param value the attribute value to match
     */
    public void setAttr(final String name, final String value) {

    printEvent("callStart");
  }

  @Override public void callEnd(Call call) {
    printEvent("callEnd");
  }

  ...
}
```

We can use this listener to race a pair of concurrent HTTP requests:

```java
Request washingtonPostRequest = new Request.Builder()
    .url("https://www.washingtonpost.com/")
    .build();
client.newCall(washingtonPostRequest).enqueue(new Callback() {

        if (StringUtil.isBlank(ruleString)) {
            return childUrlRuleMap.entrySet().stream().map(e -> new Pair<>(e.getKey(), e.getValue()));
        }
        return Arrays.stream(ruleString.split(","))
                .map(s -> s.split(":"))
                .filter(v -> v.length == 2)
                .map(v -> new Pair<String, String>(v[0].trim(), v[1].trim()));
    }

    /**

import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.codelibs.core.io.FileUtil;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.core.misc.Pair;
import org.codelibs.core.misc.Tuple3;
import org.codelibs.fess.exception.FessSystemException;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.unit.UnitFessTestCase;

      } else {
        utf8Length += 2;
        // We can't use Character.isSurrogate(c) here and below because of GWT.
        if (MIN_SURROGATE <= c && c <= MAX_SURROGATE) {
          // Check that we have a well-formed surrogate pair.
          if (Character.codePointAt(sequence, i) == c) {
            throw new IllegalArgumentException(unpairedSurrogateMsg(i));
          }
          i++;
        }
      }
    }
    return utf8Length;
  }

    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

    // Lock while we check state. We must maintain the lock while adding the new pair so that
    // another thread can't run the list out from under us. We only add to the list if we have not
    // yet started execution.
    synchronized (this) {
      if (!executed) {

    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

    // Lock while we check state. We must maintain the lock while adding the new pair so that
    // another thread can't run the list out from under us. We only add to the list if we have not
    // yet started execution.
    synchronized (this) {
      if (!executed) {

  }

  private LinkedListMultimap(Multimap<? extends K, ? extends V> multimap) {
    this(multimap.keySet().size());
    putAll(multimap);
  }

  /**
   * Adds a new node for the specified key-value pair before the specified {@code nextSibling}
   * element, or at the end of the list if {@code nextSibling} is null. Note: if {@code nextSibling}
   * is specified, it MUST be for a node for the same {@code key}!
   */

     * Gets the query builder for this context.
     * @return The query builder.
     */
    public QueryBuilder getQueryBuilder() {
        return queryBuilder;
    }

    /**
     * Adds a field and text pair to the field log for tracking query terms.
     * @param field The field name.
     * @param text The query text for this field.
     */
    public void addFieldLog(final String field, final String text) {

import okio.Buffer
import okio.ForwardingSink
import okio.ForwardingSource
import okio.Sink
import okio.Socket
import okio.Source
import okio.buffer

/**
 * Transmits a single HTTP request and a response pair. This layers connection management and events
 * on [ExchangeCodec], which handles the actual I/O.
 */
class Exchange(
  internal val call: RealCall,
  internal val eventListener: EventListener,