Doing a MTU exchange

[maelp]

It's not clear to me how we initiate a MTU negotiation, in particular on osX or webbluetooth? Is there a method to call?

On my end, the peripheral.mtu is always null?

[maelp]

I see there is a exchangeMtu in Gatt, but not sure how to build this object / initialize it in the normal flow of operations? Also does that work cross-platforms (osx, linux, webbluetooth)?