static simgrid::xbt::signal<void(kernel::activity::ExecImplPtr)> onCreation;
static simgrid::xbt::signal<void(kernel::activity::ExecImplPtr)> onCompletion;
static simgrid::xbt::signal<void(simgrid::kernel::activity::ExecImplPtr, simgrid::s4u::Host*)> onMigration;
static simgrid::xbt::signal<void(kernel::activity::ExecImplPtr)> onCreation;
static simgrid::xbt::signal<void(kernel::activity::ExecImplPtr)> onCompletion;
static simgrid::xbt::signal<void(simgrid::kernel::activity::ExecImplPtr, simgrid::s4u::Host*)> onMigration;