private void addToRssiLog(final long timestamp, final int rssiReading) {
        synchronized (mRssiLog) {
            if (timestamp - mCurrentTimestamp > LOG_INVALIDATION_THRESHOLD) {
                mRssiLog.clear();
            }

            mCurrentRssi = rssiReading;
            mCurrentTimestamp = timestamp;
            mRssiLog.put(timestamp, rssiReading);
        }
    }
Adds the to rssi log.

@param timestamp   the timestamp
@param rssiReading the rssi reading
library/src/main/java/dev/alt236/bluetoothlelib/device/BluetoothLeDevice.java