*
 * <p><b>Note:</b> by default, the returned cache uses equality comparisons (the {@link
 * Object#equals equals} method) to determine equality for keys or values. However, if {@link
 * #weakKeys} was specified, the cache uses identity ({@code ==}) comparisons instead for keys.
 * Likewise, if {@link #weakValues} or {@link #softValues} was specified, the cache uses identity
 * comparisons for values.
 *

   * This is not the same definition used by other Java APIs. (See a <a
   * href="https://docs.google.com/spreadsheets/d/1kq4ECwPjHX9B8QUCTPclgsDCXYaj7T-FlT4tB5q3ahk/edit">comparison
   * of several definitions of "whitespace"</a>.)
   *
   * <p>All Unicode White_Space characters are on the BMP and thus supported by this API.
   *