Introduce a `size_t` field into the rax struct to track allocation size.
Update the allocation size on rax insert and deletes.
Return the allocation size when `raxAllocSize` is called.
This size tracking is now used in MEMORY USAGE and MEMORY STATS in place
of the previous method based on sampling.
The module API allows to create sorted dictionaries, which are backed by
rax. Users now also get precise memory allocation for them (through
`ValkeyModule_MallocSizeDict`).
Fixes#677.
For the release notes:
* MEMORY USAGE and MEMORY STATS are now exact for streams, rather than
based on sampling.
---------
Signed-off-by: Guillaume Koenig <knggk@amazon.com>
Signed-off-by: Guillaume Koenig <106696198+knggk@users.noreply.github.com>
Co-authored-by: Joey <yzhaon@amazon.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
