Perfect

- Make original buffer use a disk backed mapping to save memory.
- rearrange api function headers for search etc.
- fix bugs with iterators.
- support uint64_t for all byte and line offsets to allow for much larger files to be opened.
- and more minor bug fixes.

include/vase/buffer/buffer.h

@@ -3,7 +3,7 @@
 #include "pch.h"
 
 struct Buffer {
-  virtual const char *read(uint32_t pos, uint32_t *out_len) = 0;
-  virtual inline uint32_t length() = 0;
+  virtual const char *read(uint64_t pos, uint64_t *out_len) = 0;
+  virtual inline uint64_t length() = 0;
   virtual ~Buffer() = default;
 };