public static BlobAssetReference <QuadTree> CreateBlobAssetReference()
{
using (var builder = new BlobBuilder(Allocator.Temp)) {
ref var rootQuadTree = ref builder.ConstructRoot <QuadTree>();
var colliders = builder.Allocate(ref rootQuadTree.Colliders, 2);
LineCollider.Create(builder, ref colliders[0], new float2(1f, 20f), new float2(3f, 4f), 5f, 6f);
PointCollider.Create(builder, ref colliders[1], new float3(7f, 8f, 9f));
return(builder.CreateBlobAssetReference <QuadTree>(Allocator.Persistent));
}