chore: update time callback error non-strings

tests/test-timer.lua

@@ -115,12 +115,27 @@ return require('lib/tap')(function (test)
  assert(huge_timer:get_due_in()==0xffff)
  end, "1.40.0")
 
- test("timer init", function(print, p, expect, uv)
+ test("timer callback with errors", function(print, p, expect, uv)
+ local Error = {}
+ Error.__index = Error
+
+ function Error.new(msg)
+ local o = setmetatable({}, Error)
+ o.msg = msg
+ return o
+ end
+
+ function Error:__tostring()
+ return self.msg
+ end
+
  local timer = uv.new_timer()
  timer:start(10, 0, function()
  timer:stop()
  timer:close()
- error('Error in timeout callback')
+ local e = Error.new('Error in timeout callback')
+ print('e:', e)
+ error(e)
  end)
  end)
 end)