Replace caching with memory mapping #15
Description
Memory mapping avoids unneeded allocation for the read-cache. Additionally the file itself does not need to be loaded at all.
The operating system will handle it for you.
Memory advicing (madvice) may be a good addition here.
UNIX
https://man7.org/linux/man-pages/man2/mmap.2.html
Windows
https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createfilemappinga