pub unsafe fn WsAddMappedHeader(
    message: *const WS_MESSAGE,
    headername: *const WS_XML_STRING,
    valuetype: WS_TYPE,
    writeoption: WS_WRITE_OPTION,
    value: *const c_void,
    valuesize: u32,
    error: Option<*const WS_ERROR>
) -> Result<()>