Validations::withTrie

Use the trie for a calculation.

template<
    class F>
auto
withTrie(
    ScopedLock const& lock,
    F&& f);

Accessing the trie through this helper ensures acquiring validations are checked and any stale validations are flushed from the trie.

Name	Description
`lock`	Existing locked of mutex_
`f`	Invokable with signature (LedgerTrie<Ledger> &)

The invokable f is expected to be a simple transformation of its arguments and will be called with mutex_ under lock.