Package warmup allows to register hooks executed during the server warmup.
All registered hooks should be optional. The warmup stage can be skipped.
InstallHandlersDeprecated installs HTTP handlers for warmup /_ah/* routes.
It is deprecated. Do not use. On GAEv1 it is called by the framework code. On GAEv2 or on GKE use NewModuleFromFlags() and register the warmup module when starting the server.
Register adds a callback called during warmup.