Trouble with: setAdvertising heart_rate

Ok, this is now done and will be in 1v92. You can do:

NRF.setServices({
  0x180D: { // heart_rate
    0x2A37: { // heart_rate_measurement
      notify: true,
      value : [0x06, hr],
    },
    0x2A38: {
      readable: true,
      value: [0x02]
    }
  }
}, {advertise:[0x180D]});

to start advertising the heart rate service.