升级到2.6.0之后，通过edge文件下载功能出现异常导致文件内容不完整

升级到2.6.0之后，通过edge文件下载功能出现异常导致文件内容不完整，请求通过edge转发到下层Rest服务，直接调用Rest服务返回的文件是好的，但是通过edge调用之后文件内容不完整，具体表现是图片花屏、excel打不开；把edge回退到2.2版本就恢复正常了

Reproduce the incomplete download through the edge file-download path using an image or Excel file, then compare it with direct calls to the lower-level REST service. Compare the edge behavior in 2.6.0 with 2.2, and consider the issue resolved when files forwarded through edge match the direct REST responses and open correctly.

Written by the indexing model from the issue text.