jbe/bsw@0: function trace._close_section()
jbe/bsw@0:   local pos = #trace._stack
jbe/bsw@0:   local closed_section = trace._stack[pos]
jbe/bsw@0:   if not closed_section then
jbe/bsw@0:     error("All trace sections have been closed already.")
jbe/bsw@0:   end
jbe/bsw@0:   trace._stack[pos] = nil
jbe/bsw@0:   return closed_section
jbe/bsw@0: end