ameter name. For example, <code>("request", "para", c(1, 2))</code> will
return "request?para=1&amp;para=2".</p></li>
<li><p>"with_commas". The values of the parameter are concatenated and
separated with commas. For example, <code>("request", "para", c(1, 2))</code> will
return "request?para=1,2".</p></li>
<li><p>"with_commas". The values of the parameter are concatenated and
separated with the ASCII keycode in hexadecimal for a comma ("%2C"). For
example, <code>("request", "para", c(1, 2))</code> will retu