add a place holder for later merge consecutive chunks

weed/server/filer_server_handlers_write_merge.go

@@ -0,0 +1,11 @@
+package weed_server
+
+import (
+	"github.com/chrislusf/seaweedfs/weed/operation"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+)
+
+func (fs *FilerServer) maybeMergeChunks(so *operation.StorageOption, inputChunks []*filer_pb.FileChunk) (mergedChunks []*filer_pb.FileChunk, err error) {
+	//TODO merge consecutive smaller chunks into a large chunk to reduce number of chunks
+	return inputChunks, nil
+}