handler_table
A lock-free table of event handlers.
Examples
use HandlerTable;
static TABLE: = new;
TABLE.register_handler;
TABLE.register_handler;
assert!; // print "Hello, event 0!"
assert!; // unregistered
assert!;
let func = TABLE.unregister_handler.unwrap; // retrieve the handler
func; // print "Hello, event 1!"
assert!; // unregistered