Rename functions returning distances between buffer pointers:
* `buffer_size()` → `start_to_limit()`
* `{written_to,read_from}_buffer()` -> `start_to_cursor()`
This avoids a naming conflict with a `buffer_size()` setting in various
`Options`, avoids a weird case when only one buffer-related name differs between
`Reader` and `Writer`, and is more explicit.
`available()` stays unchanged. It is fundamental when reading/writing directly
at `cursor()` so it can have a shorter name.
PiperOrigin-RevId: 406318134
Riegeli/records is a file format for storing a sequence of string records, typically serialized protocol buffers. It supports dense compression, fast decoding, seeking, detection and optional skipping of data corruption, filtering of proto message fields for even faster decoding, and parallel encoding.
See documentation.
Riegeli file format will only change in a backward compatible way (i.e. future readers will understand current files, but current readers might not understand files using future features).
Riegeli C++ API might change in incompatible ways.