ability to send faster Serial / ASYNC on physical pin

[CaptainCredible]

Is your feature request related to a problem? Please describe.
Serial transmission over a physical pin is slow, specifically it takes a long time between messages sent. For me personally this creates problems when sending MIDI messages directly to physical synths via a physical pin. It can take 10ms between sending notes which leads to staggered notes when attempting to play a chord, or trigger multiple drums simultaniously.

Describe the solution you'd like
The ability to send midi messages faster. The microbit dal serial drivers can send ASYNC:
https://github.com/lancaster-university/microbit-dal/blob/master/source/drivers/MicroBitSerial.cpp#L294
It would be great if this was accessible via javascript in the makecode editor.

Describe alternatives you've considered
Use i2c between the microbit and a second microcontroller that in turn then sends MIDI messages to synths.

Additional context
Not sure if this is related, but when receiving serial data at MIDI baudrate I the microbit loses so many bytes that it becomes inpractical to use (therefore i have resorted to using i2c here too).

[Makeadrone]

I have the problem with receiving serial data at baud rate 115200. After a while the micro:bit stops to receive any data at all.