title: Negotiate BLE MTU on iOS
body: <p>I'm currently developing a BLE App for iOS.
  In my application I need to implement a segmentation protocol to send large quantities of data using BLE.
  My application need to have the Central role.</p>
  <p>My issue is that I can't get the negotiate MTU. I can get the <code>maximumWriteValueLength</code> of my peripheral but it is bigger that mine and can't find the <code>maximumWriteValueLength</code> of my central object.</p>
  <p>Does someone know a way to find the negotiated MTU or a way to access the <code>CBCentral</code> object of my <code>CBCentralManager</code>?</p>