+// BuildMergeHeap holds the merges that can start, by the end of their context.
+type BuildMergeHeap []NodeKey
+
+func newBuildQueue() *BuildQueue {
+ return &BuildQueue{
+ queued: make(map[NodeKey]bool),
+ running: make(map[NodeKey]bool),
+ failed: make(map[NodeKey]bool),
+ }
+}
+