* purposes, the "count" field, tracking the number of elements, serves as that volatile
     * variable ensuring visibility. This is convenient because this field needs to be read in many
     * read operations anyway:
     *
     * - All (unsynchronized) read operations must first read the "count" field, and should not look
     * at table entries if it is 0.
     *

her feet, for it flashed across her mind that she had never
before seen a rabbit with either a waistcoat-pocket, or a watch to
take out of it, and burning with curiosity, she ran across the
field after it, and fortunately was just in time to see it pop
down a large rabbit-hole under the hedge.

  In another moment down went Alice after it, never once
considering how in the world she was to get out again.

     * purposes, the "count" field, tracking the number of elements, serves as that volatile
     * variable ensuring visibility. This is convenient because this field needs to be read in many
     * read operations anyway:
     *
     * - All (unsynchronized) read operations must first read the "count" field, and should not look
     * at table entries if it is 0.
     *

    // Since holder.value is 2, applying 4 should yield 6.
    assertEquals(6, adder.apply(4).intValue());

    ListenableFuture<Integer> immediateFuture = immediateFuture(4);
    Future<Integer> transformedFuture = transform(immediateFuture, adder, directExecutor());

    // The composed future also yields 6.
    assertEquals(6, getDone(transformedFuture).intValue());

    // Repeated calls yield the same value even though the function's behavior

    // Since holder.value is 2, applying 4 should yield 6.
    assertEquals(6, adder.apply(4).intValue());

    ListenableFuture<Integer> immediateFuture = immediateFuture(4);
    Future<Integer> transformedFuture = transform(immediateFuture, adder, directExecutor());

    // The composed future also yields 6.
    assertEquals(6, getDone(transformedFuture).intValue());

    // Repeated calls yield the same value even though the function's behavior

her feet, for it flashed across her mind that she had never
before seen a rabbit with either a waistcoat-pocket, or a watch to
take out of it, and burning with curiosity, she ran across the
field after it, and fortunately was just in time to see it pop
down a large rabbit-hole under the hedge.

  In another moment down went Alice after it, never once
considering how in the world she was to get out again.