IDisposable & using Statement

The garbage collector handles managed memory automatically, but plenty of resources sit outside its reach: open file handles, network sockets, database connections, native memory buffers, and operating-system primitives like mutexes and timers. These resources need to be released at a precise moment, not "eventually when the GC feels like it." This lesson covers the IDisposable interface, the using statement and using declaration that drive deterministic cleanup, the full Dispose pattern for class hierarchies, and the async equivalents introduced in C# 8.