The WebViewClient provides hooks for capturing various events such as page load start and end, form re-submission, keyboard intercepting, and many other events programmers love to trap and manipulate.
Subflows, introduced in v6.2 of Process Server and WESB, are a way of capturing a set of mediation steps (primitives, like the ones in Figure 15) in a re-useable flow fragment.
Process Server和WESB v6.2中引入的子流指一种在可重用流片段中捕捉一组中介步骤(原语，如图15所示)的方式。