And refactor some code a bit, don't use bytes.Clone where type-specific
helpers may be used instead.
Close#2907.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
They never return errors, so their interface should reflect that. This allows
to remove quite a lot of useless and never tested code.
Notice that Get still does return an error. It can be made not to do that, but
usually we need to differentiate between successful/unsuccessful accesses
anyway, so this doesn't help much.
We use them quite frequently (consider children for a new branch
node) and it is better to get rid of unneeded allocations.
Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>
