Implementing a worker pool

Often in time when you need to execute multiple tasks it pays off to run them in parallel, especially when they involve blocking I/O operations.Often in time when you need to execute multiple tasks it pays off to run them in parallel, especially when they involve blocking I/O operations. However, it may not always be possible to spin as many threads as the number of tasks, think about the maximum number of connections allowed to a database server or threads that could use large chunks of memory.