Replace ErrNotFound and ErrRangeOutOfBounds to core/object package in order
to share them across the libraries.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation Shard accessed the BlobStor to get the
object header. However, the shard must take headers from the metabase.
From now zero length of the requested payload range seens as object
header request. In this case shard calls metabase to get the header.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation each shard operation locked
RW shard mutex. With this approach RW operations were executed
one-by-one and blocked the execution of RO operations.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
