// We use all core threads (the first 2 parameters below equal) so, when a task is submitted,
// if the thread limit hasn't been reached, a new thread will be spawned to execute
// the task even if there is an existing idle thread in the pool. This is faster than
// We use all core threads (the first 2 parameters below equal) so, when a task is submitted,
// if the thread limit hasn't been reached, a new thread will be spawned to execute
// the task even if there is an existing idle thread in the pool. This is faster than