Maximize throughput

[hathach]

• add requestPHY() to switch to 2MB PHY, fix High Throughput (2 Mbps PHY) support #83 PHY selection support #80
• add requestDataLengthUpdate() to increase data length BLE 4.2 Data Length Update (link layer) #85
• add requestMtuExchange() to actively exchange MTU, fix Self initiate MTU exchange #106

update throughput example, and added central_throughput example

[tilink]

Is Coded PHY (Long Range) supported now because of this? You say in #223 "implemented by PR #324" #223 (comment) which makes me believe that is the case. However there is another open issue #82 that is specifically for Long Range that shows no support so far.

Can I just request PHY Coded the same way you added the 2Mbps support/example?
conn->requestPHY(BLE_GAP_PHY_CODED);

[hathach]

@tilink sorry, that was my mistake, just reopen the other issue. Long range with coded phy is not supported yet.