perf: do a bulk insert in fetchCollection

Improve performance over inserting each item individually

pkg/platform.go

@@ -1,5 +1,7 @@
 package synchronizator
 
+import "slices"
+
 type PlatformClass interface {
 	// How to transform the struct into a node. It needs to return the class,
 	// name and a []byte representation of the metadata.
@@ -24,7 +26,7 @@ type Platform struct {
 	collections []*Collection // Child nodes
 }
 
-type Fetcher = func(conn *DB, pagination Pagination) ([]*Collection, Pagination, error)
+type Fetcher = func(pagination Pagination) ([]*Collection, Pagination, error)
 
 type Pagination struct {
 	Total   int
@@ -41,14 +43,17 @@ var StartPagination = Pagination{
 }
 
 func (platform *Platform) FetchCollections(fetcher Fetcher, start_pagination Pagination) error {
-	collections, pagination, err := fetcher(platform._conn, start_pagination)
+	collections, pagination, err := fetcher(start_pagination)
 	if err != nil {
 		return err
 	}
-	platform.collections = collections
+	platform.collections = slices.Concat(platform.collections, collections)
 
 	if pagination.HasMore {
 		return platform.FetchCollections(fetcher, pagination)
 	}
+
+	err = BulkCreateNode(platform._conn, platform.collections)
+
 	return nil
 }