Add pub fn to impl and make ffi function private so as not to expose Heartbeat
Add pub fn to impl and make ffi function private so as not to expose Heartbeat

vvuk/heartbeats-simple-sys,connorimes/heartbeats-simple-sys,libheartbeats/heartbeats-simple-sys,libheartbeats/heartbeats-simple-sys,connorimes/heartbeats-simple-sys,vvuk/heartbeats-simple-sys