Threads

Process
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OS facilitates the execution of the program by providing the resources required. each process has a unique process ID

Threads
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Inside Process, there might be one(main thread) to many lightweight processes has. Those are called threads

Advantages of thread

1. to maintain a responsive user interface.
2. to split large ask to small task and give deferent cpu to complete them.

Disadvantages

1. need to consider thread safe,context switch.

Example 1

Without threads

for print success (on main thread) this will wait for complete TimeConsumingWork

With Threads

Main Thread will not pouse for complete time-consuming task. because it is on another thread

Thread Start Delegate

To start a thread, for Thread class we need to pass not a function but function pointer. delegate is the function pointer. when execute var t = new Thread(TimeConsumingWork); behind the seen program creates function pointer to TimeConsumingWork and pass to the Thread Class implicitly. but for more understand we can use ThreadStart delegate in deferent ways.

1.  var threadStartDelegate = new ThreadStart(TimeConsumingWork);
    var thread = new Thread(threadStartDelegate);
2.  var t = new Thread(() => TimeConsumingWork());
3.   var t = new Thread(delegate () { TimeConsumingWork(); });

ParameterizedThreadStart delegate
   
  If need to pass some parameters to the method we can use parameterizedThreadStart delegate

Retrieving data from thread function

Thread Chaining

Task.Run(async () =>
{
    await LongTaskAsync("A");
    await LongTaskAsync("B");
    await LongTaskAsync("C");
});

Thread.Join.

Block the current thread and wait untile all join threads are complete.Thread.Join has overrload method that specify the timeout.

without join

with join

with Join(timeout);

if timeout exceeded, main thread continue. but after particular thread will finish there work

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Comparison

Without Concurrency or parallelism 

With Async await 1

With Async Await 2

Using Threads/parallelism