Summary:
This diff improves the performance of `PropertyStore` with two main
techniques:
First:
`PropertyValue` has a very expensive constructor and destructor. The
`PropertyValue` was previously passed as a return value from many functions
wrapped in a `std::optional`. That caused the `PropertyValue`
constructor/destructor to be called for each intermediary value that was passed
between functions. This diff changes the functions to return a `bool` value
that imitates the `std::optional` "emptyness" flag and the `PropertyValue` is
modified using a pointer to it so that its constructor/destructor is called
only once.
Second:
The `PropertyStore` buffer was previously iterated through at least twice.
First to determine the exact position of the encoded property and then to
actually decode the property. This diff combines the two passes into a single
pass so that the property is immediately loaded if it is found.
Reviewers: buda
Reviewed By: buda
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2766
