Directs tracing or debugging output to a text writer , such as a stream writer , or to a stream , such as a file stream 将跟踪或调试输出定向到文本编写器（例如流编写器） ，或定向到流（例如文件流） 。
Indicating that the stream is flushed after every write ; otherwise the log entries are buffered and written more efficiently 指示每次写入之后都刷新日志文件流；否则将缓存日志条目，这样写入会更有效率。
The code below demonstrates how to load the file located on the server into the stream and store it to the http response stream 下面的代码演示了怎样加载服务器上的文件使生成文件流，并保存到http响应流中。
A file based persistent store in which streams can be created and objects externalised to them but , once committed and closed , they cannot subsequently be changed 直接文件存储：基于永久存储的文件，可创建并具体化文件流，一旦完成或者关闭，文件不能被改变。
Problem . to resolve this , once you create a temporary file atomically , you must always use the file descriptor or file stream you got when you opened the file 解决这种问题的方法是，一旦自动创建了一个临时文件，就必须始终使用打开该文件时得到的文件描述符或文件流。
