*       <blockquote>
   *       maxPermits = thresholdPermits + 2 * warmupPeriod / (stableInterval + coldInterval)
   *       </blockquote>
   * </ul>
   */
  static final class SmoothWarmingUp extends SmoothRateLimiter {
    private final long warmupPeriodMicros;
    /**
     * The slope of the line from the stable interval (when permits == 0), to the cold interval
     * (when permits == maxPermits)

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Stopwatch;
import com.google.common.util.concurrent.SmoothRateLimiter.SmoothBursty;
import com.google.common.util.concurrent.SmoothRateLimiter.SmoothWarmingUp;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
import javax.annotation.CheckForNull;

/**

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Stopwatch;
import com.google.common.util.concurrent.SmoothRateLimiter.SmoothBursty;
import com.google.common.util.concurrent.SmoothRateLimiter.SmoothWarmingUp;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
import javax.annotation.CheckForNull;

/**