mmap() function

The `mmap()` function creates a direct connection between a file and a part of your program's memory, allowing the program to read and write to the file as if it were a regular memory array. Instead of reading and writing data in chunks, `mmap()` maps the file into memory, making operations faster and more efficient. This approach simplifies handling large files and can improve performance for file processing tasks by eliminating the need for explicit read/write system calls. Once mapped, changes in memory can be saved back to the file or discarded, depending on the specified options.