ble_app_uart is too slow for IOS,how to fix it?

[qoboty]

I use ble_app_uart of IOS,but the Tx speed is about 200B/s(send 20B for 100ms), why ? how to speed up to 20KB/s ? Thank you!

[qoboty]

I use android to send 20 bytes only using 5ms, Speed is 4KB/s, why ios is so slow ?? how to fix it ??