Why do we use request instead of send ?

[demirbey05]

In this test code :

it("Should emit the error when user try to enter in calculating state", async () => {
                  await raffle.enterRaffle({ value: entranceFee })
                  await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
                  await network.provider.request({ method: "evm_mine", params: [] })
                  await raffle.performUpkeep([])
                  await expect(raffle.enterRaffle({ value: entranceFee })).to.be.revertedWith(
                      "Raffle__NotOpen"
                  )
              })

We used firstly send then request for second rpc call, why do we used request instead of send ?