I've been trying to use TLS to invoke a Slack webhook but it seems that TLS library
consumes too much memory and finally malloc fails and crashes.
I allocated 20KB for heap memory. Refer: https://plot.ly/~seiyanuta/8/?share_key ... PmbS0WHi9Y
In Time > 600, esp8266 starts a TLS connection and consumes too much heap.
Does anyone know how much heap memory do we need for TLS?