This document provides an overview of the Reentrancy library.
It outlines the use cases and specification.
The reentrancy check is used to check if a contract ID has been called more than once in the current call stack.
A reentrancy, or "recursive call" attack (example here can cause some functions to behave in unexpected ways. This can be prevented by asserting a contract has not yet been called in the current transaction.
Reverts if the current call is reentrant.
Returns true if the current contract ID is found in any prior contract calls.