问为什么对内存优化的非持久表的大容量插入速度与持久表相同？

EN

CREATE TABLE Users_ND (
  Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY NONCLUSTERED HASH WITH (BUCKET_COUNT=10000000),  
  Username VARCHAR(200) NOT NULL  
) WITH (MEMORY_OPTIMIZED=ON, DURABILITY = SCHEMA_ONLY);  

CREATE TABLE Users_D (
  Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY NONCLUSTERED HASH WITH (BUCKET_COUNT=10000000),  
  Username VARCHAR(200) NOT NULL  
) WITH (MEMORY_OPTIMIZED=ON, DURABILITY = SCHEMA_AND_DATA);  

SET STATISTICS TIME ON;
SET NOCOUNT ON;  

BULK INSERT Users_ND 
FROM 'users-huge.csv' 
WITH (FIRSTROW = 2, FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', BATCHSIZE = 1000000);

BULK INSERT Users_D 
FROM 'users-huge.csv' 
WITH (FIRSTROW = 2, FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', BATCHSIZE = 1000000);

Id, Username
,user1
,user2
...
,user10000000