[#211] blobstor: Define GetRangeSmall operation interface

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/local_object_storage/blobstor/get_range_small.go

@@ -0,0 +1,24 @@
+package blobstor
+
+// GetRangeSmallPrm groups the parameters of GetRangeSmall operation.
+type GetRangeSmallPrm struct {
+	address
+	rwRange
+	rwBlobovniczaID
+}
+
+// GetRangeSmallRes groups resulting values of GetRangeSmall operation.
+type GetRangeSmallRes struct {
+	rangeData
+}
+
+// GetRangeSmall reads data of object payload range from blobovnicza of BLOB storage.
+//
+// If blobovnicza ID is not set or set to nil, BlobStor tries to get payload range
+// from any blobovnicza.
+//
+// Returns any error encountered that
+// did not allow to completely read the object payload range.
+func (b *BlobStor) GetRangeSmall(prm *GetRangeBigPrm) (*GetRangeBigRes, error) {
+	panic("implement me")
+}