[#211] blobstor: Add SmallSizeLimit parameter

Add numeric parameter of maximum size of the "small" objects.

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

pkg/local_object_storage/blobstor/blobstor.go

@@ -22,6 +22,8 @@ type cfg struct {
 	compressor func([]byte) []byte
 
 	decompressor func([]byte) ([]byte, error)
+
+	smallSizeLimit uint64
 }
 
 const (
@@ -39,8 +41,9 @@ func defaultCfg() *cfg {
 				RootPath:    "./",
 			},
 		},
-		compressor:   noOpCompressor,
-		decompressor: noOpDecompressor,
+		compressor:     noOpCompressor,
+		decompressor:   noOpDecompressor,
+		smallSizeLimit: 1 << 20,
 	}
 }
 
@@ -117,3 +120,11 @@ func WithTreeRootPerm(perm os.FileMode) Option {
 		c.fsTree.Permissions = perm
 	}
 }
+
+// WithSmallSizeLimit returns option to set maximum size of
+// "small" object.
+func WithSmallSizeLimit(lim uint64) Option {
+	return func(c *cfg) {
+		c.smallSizeLimit = lim
+	}
+}