ConvertToString convert struct to string.

ConvertToStringWithTitle convert struct to string with given title.

NewErrMessage returns a *ErrMessage without stack trace, note that if errs contains more than one error, only the first one will be used, if you want to use more than one error, please use github.com/romberli/go-multierror to wrap those errors to one.

WriteToBuffer loops each member of given input struct recursively, converts member variable names and concerning values to "key = value" string, and then write the string into buffer, it follows some rules: 1.