return response;
  }
}
```

A call to `chain.proceed(request)` is a critical part of each interceptor’s implementation. This simple-looking method is where all the HTTP work happens, producing a response to satisfy the request. If `chain.proceed(request)` is being called more than once previous response bodies must be closed.

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.concurrent

/**
 * A unit of work that can be executed one or more times.
 *
 * Recurrence
 * ----------
 *
 * Tasks control their recurrence schedule. The [runOnce] function returns -1L to signify that the

  SampleElements<E> samples();

  /**
   * Creates a new container containing the given elements. TODO: would be nice to figure out how to
   * use E... or E[] as a parameter type, but this doesn't seem to work because Java creates an
   * array of the erased type.
   */
  T create(Object... elements);

  /**
   * Helper method to create an array of the appropriate type used by this generator. The returned

    }
    return x;
  }

  @CanIgnoreReturnValue
  static double checkNonNegative(String role, double x) {
    if (!(x >= 0)) { // not x < 0, to work with NaN.
      throw new IllegalArgumentException(role + " (" + x + ") must be >= 0");
    }
    return x;
  }

  static void checkRoundingUnnecessary(boolean condition) {
    if (!condition) {

import org.junit.runners.Parameterized.Parameters;

/** Tests for {@link MapIteratorCache} and {@link MapRetrievalCache}. */
@AndroidIncompatible
// TODO(cpovirk): Figure out Android JUnit 4 support. Does it work with Gingerbread? @RunWith?
@RunWith(Parameterized.class)
@NullUnmarked
public final class MapCacheTest {
  private final MapIteratorCache<String, String> mapCache;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *