Because trie size is rather big, it can't be stored in memory.
Thus some form of caching should also be implemented. To avoid
marshaling/unmarshaling of items which are close to root and are used
very frequenly we can save them across the persists.
This commit implements pruning items at the specified depth,
replacing them by hash nodes.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Because there is no distinct type field in JSONized nodes, distinction
is made via payload itself, thus all unmarshaling is done via
NodeObject.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
MPT is a trie with a branching factor = 16, i.e. it consists of sequences in
16-element alphabet.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
