In previous implementation node's Object Get/Head/GetRange V2 service
handlers created a new request for each RPC. Now original requests are
re-signed according to API specification. Logical handler abstracts from
this version-dependent logic through `RequestForwarder` callback.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Support processing of NetmapEpoch and NetmapLookupDepth X-headers when
processing object read operations. Placement for operations
Get/Head/GetRange/GetRangeHash/Search is built for the epoch specified in
NetmapEpoch X-header (by default latest). Also the specified operations are
processed until success is achieved for network maps from the past up to
NetmapLookupDepth value. Behavior for default values (zero or missing) left
unchanged.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
