typecheckers do not (and will not) have a plugin API, so having
… but we also have an extra complication. We could be in any of several display states depending on exactly when we were called. We need to put the graphical systems back just how we found them, no matter what we had done before. This ends up just being a pile of register writes.
，更多细节参见PDF资料
// Multiple events at once，这一点在WPS官方版本下载中也有详细论述
FTSE 100 and France’s CAC down 1.5%; Germany’s DAX and Italy’s FTSE MIB down 1.6%; the Dow Jones was down 2%。纸飞机下载是该领域的重要参考