* reduce extractions to projections
* recycle string buffers in SocketTask
* micro optimizations for mmfiles indexes
* added special lookup function for _key
* moved function into the correct file
* speed up key buffer allocations a bit
* added noexcept specifier
* correctly name variable
* explicitly move bounds
* fix and speedup from/toPersistent functions
* reuse string from ManagedDocumentResult for multiple lookups
* use move-assign
* a bit less work for single server
* speedup AQL function HASH
* single fetch optimization
* performance optimization for the case when no documents need to be returned
* make reduce-extraction-to-projection a RocksDB-only optimizer rule
* cppcheck
* try to fix compile error on MacOS
* bug fix for MacOSX
* missing namespace (in Windows compile)
* Take out 503 timeouts altogether.
* Overhaul of AgencyComm::sendWithFailover loop.
* Let performRequests optionally ignore 404 coll not found.
* Fix error message "database not found" when AgencyComm failed.
* Add log entries in Agency if locks are acquired too slowly.
* Reexecute the javascript cluster sync stuff even if there was no plan/current change...So failed sync jobs can retry later...
* Cover callbacks in Communicator by lock. This fixes https://github.com/arangodb/planning/issues/370
* Put in delay in waiting for leader in agency test.
* Schmutz logging to heartbeat topic.
* Add more lock time diagnostic in agent.
* Switch on agencycomm tracing in coordinator.
so that other features can indicate that they need a storage engine
but do not need to reference a concrete storage engine such as "mmfiles"
or "rocksdb"
* reduce extractions to projections
* recycle string buffers in SocketTask
* micro optimizations for mmfiles indexes
* added special lookup function for _key
* moved function into the correct file
* speed up key buffer allocations a bit
* added noexcept specifier
* correctly name variable
* explicitly move bounds
* fix and speedup from/toPersistent functions
* reuse string from ManagedDocumentResult for multiple lookups
* use move-assign
* a bit less work for single server
* speedup AQL function HASH
* single fetch optimization
* performance optimization for the case when no documents need to be returned
* make reduce-extraction-to-projection a RocksDB-only optimizer rule