The code of Example 13.35 could fairly be accused of displaying poor abstraction. If we make desired condition a delegate (a subroutine or object closure), can we pass it as an extra parameter, and...

The code of Example 13.35 could fairly be accused of displaying poor abstraction. If we make desired condition a delegate (a subroutine or object closure), can we pass it as an extra parameter, and move the signal and scheduler lock management inside sleep on? (Hint: Consider the code for the P operation in Figure 13.15.)