Why do we have to pass a pointer to a `std::string` to `Get()` ?

This requires us to first default construct a `std::string`, and then pass its address to the `Get()` function. But what if i'm only interested in if the key is in the database? In this case, isn't the construction of the std::string is entirely useless? The copying of the lookup result will also be a significant overhead. What am I missing here? Thanks in advance.

Start by reviewing the Get() API and its documented lookup behavior. Determine whether existence-only checks are already supported; if not, the work would need a clearly defined API proposal and acceptance criteria for avoiding unnecessary value construction and copying.

Written by the indexing model from the issue text.