/// <summary>
        /// <para>Await until the given condition evaluates to <c>true</c> or the timeout
        /// expires, whichever comes first.</para>
        /// <para>If no timeout is given, take it from the innermost enclosing `within`
        /// block.</para>
        /// <para>Note that the timeout is <see cref="Dilated(TimeSpan)">dilated</see>, i.e. scaled by the factor 
        /// specified in config value "akka.test.timefactor".</para>
        /// <para>The parameter <paramref name="interval"/> specifies the time between calls to <paramref name="conditionIsFulfilled"/>
        /// Between calls the thread sleeps. If <paramref name="interval"/> is undefined the thread only sleeps 
        /// one time, using the <paramref name="max"/> as duration, and then rechecks the condition and ultimately 
        /// succeeds or fails.</para>
        /// <para>To make sure that tests run as fast as possible, make sure you do not leave this value as undefined,
        /// instead set it to a relatively small value.</para>
        /// </summary>
        /// <param name="conditionIsFulfilled">The condition that must be fulfilled within the duration.</param>
        /// <param name="max">The maximum duration. The value is <see cref="Dilated(TimeSpan)">dilated</see>, i.e. 
        /// scaled by the factor specified in config value "akka.test.timefactor".</param>
        /// <param name="interval">The time between calls to <paramref name="conditionIsFulfilled"/> to check
        /// if the condition is fulfilled. Between calls the thread sleeps. If undefined the thread only sleeps 
        /// one time, using the <paramref name="max"/>, and then rechecks the condition and ultimately 
        /// succeeds or fails.
        /// <para>To make sure that tests run as fast as possible, make sure you do not set this value as undefined,
        /// instead set it to a relatively small value.</para>
        /// </param>
        /// <param name="fail">Action that is called when the timeout expired. 
        /// The parameters conforms to <see cref="string.Format(string,object[])"/></param>
        /// <param name="logger">If a <see cref="ILoggingAdapter"/> is specified, debug messages will be logged using it. If <c>null</c> nothing will be logged</param>
        protected static bool InternalAwaitCondition(Func<bool> conditionIsFulfilled, TimeSpan max, TimeSpan? interval, Action<string, object[]> fail, ILoggingAdapter logger)
        {
            max.EnsureIsPositiveFinite("max");
            var start = Now;
            var stop = start + max;
            ConditionalLog(logger, "Awaiting condition for {0}.{1}", max, interval.HasValue ? " Will sleep " + interval.Value + " between checks" : "");

            while (!conditionIsFulfilled())
            {
                var now = Now;

                if (now > stop)
                {
                    const string message = "Timeout {0} expired while waiting for condition.";
                    ConditionalLog(logger, message, max);
                    fail(message, new object[] { max });
                    return false;
                }
                var sleepDuration = (stop - now).Min(interval);
                Thread.Sleep(sleepDuration);
            }
            ConditionalLog(logger, "Condition fulfilled after {0}", Now-start);
            return true;
        }
        /// <summary>
        /// <para>Await until the given condition evaluates to <c>true</c> or the timeout
        /// expires, whichever comes first.</para>
        /// <para>If no timeout is given, take it from the innermost enclosing `within`
        /// block.</para>
        /// <para>Note that the timeout is <see cref="Dilated(TimeSpan)">dilated</see>, i.e. scaled by the factor 
        /// specified in config value "akka.test.timefactor".</para>
        /// <para>The parameter <paramref name="interval"/> specifies the time between calls to <paramref name="conditionIsFulfilled"/>
        /// Between calls the thread sleeps. If <paramref name="interval"/> is undefined the thread only sleeps 
        /// one time, using the <paramref name="max"/> as duration, and then rechecks the condition and ultimately 
        /// succeeds or fails.</para>
        /// <para>To make sure that tests run as fast as possible, make sure you do not leave this value as undefined,
        /// instead set it to a relatively small value.</para>
        /// </summary>
        /// <param name="conditionIsFulfilled">The condition that must be fulfilled within the duration.</param>
        /// <param name="max">The maximum duration. The value is <see cref="Dilated(TimeSpan)">dilated</see>, i.e. 
        /// scaled by the factor specified in config value "akka.test.timefactor".</param>
        /// <param name="interval">The time between calls to <paramref name="conditionIsFulfilled"/> to check
        /// if the condition is fulfilled. Between calls the thread sleeps. If undefined the thread only sleeps 
        /// one time, using the <paramref name="max"/>, and then rechecks the condition and ultimately 
        /// succeeds or fails.
        /// <para>To make sure that tests run as fast as possible, make sure you do not set this value as undefined,
        /// instead set it to a relatively small value.</para>
        /// </param>
        /// <param name="message">The message used if the timeout expires.</param>
        /// <param name="fail">Action that is called when the timeout expired. 
        /// The parameters conforms to <see cref="string.Format(string,object[])"/></param>
        protected static void InternalAwaitCondition(Func<bool> conditionIsFulfilled, TimeSpan max, TimeSpan? interval, string message, Action<string, object[]> fail)
        {
            max.EnsureIsPositiveFinite("max");
            var stop = Now + max;
            while(!conditionIsFulfilled())
            {
                var now = Now;

                if(now > stop)
                {
                    fail("Timeout {0} expired: {1}", new object[] { max, message ?? "" });
                }
                var sleepDuration = (stop - now).Min(interval);
                Thread.Sleep(sleepDuration);
            }
        }