libcephfs: async interfaces
Implement async interfaces to libcephfs, at the least for the write and read calls.
This is motivated by the ceph vfs module in samba. Samba provides VFS interfaces to perform asynchronous I/O, which are supposed to significantly improve performance:
#1 Updated by Greg Farnum almost 8 years ago
If when we do this, whoever does so should please be careful to refactor our synchronous interfaces in terms of the async ones. The numerous paths we have through and around the librados api are really annoying and I'd like to avoid that in libcephfs as much as possible.