Then I had a look at the LiquidCrystal library and noticed that the begin function starts with a delay of 50ms created with delayMicroseconds and then several other delays are also made with delayMicroseconds so the execution will be at lest 60ms.
In this post WORKING LIBRARIES AND MODULES it is stated that the LiquidCrystal library is tested and working and also I get it working but is it safe to use it in combination with WiFi? Do I need to modify the library to use delay (ms) instead of delayMicroseconds for the longer delays?