var test =
@"{""limit"":20,""offset"":40,""moduleName"":""queryoffer"",""subDept"":"""",""deptName"":""一二三四五六七"",""underLimit"":""""}";
var charlengh = test.Length; //字符数100,因为我不用gecko,我不知道他的规则,但是你这里的表现是,他似乎并没有根据你设定的utf8规定去写长度
var bufferdata = System.Text.Encoding.UTF8.GetBytes(test);
var bytelengh = bufferdata.Length; //字节数114 ,按照uft8编码算,那里实际上是114字节