def on_trap(object_id, &block)
      raise ArgumentError, "a block must be provided" unless block
      @lock.synchronize { @oid_handler[ObjectId.new(object_id)] = block }
    end
def on_trap(object_id, &block)
      raise ArgumentError, "a block must be provided" unless block
      @lock.synchronize { @oid_handler[ObjectId.new(object_id)] = block }
    end
Define a trap handler block for a specific trap ObjectId.  This handler
 only applies to SNMPv2 traps.  Note that symbolic OIDs are not
 supported by this method (like in the SNMP.Manager class).