This post is to record the process of solving the Dragonfly Issue#1403, which is related with the optimization to the p2p uploader. To be specific, support the sendfile system call in upload piece process.
The conclusion is that, for the reader with computation task, it is impossible to use the send file to provide the fast read & write. Only the regular
io.Reader type could have this feature, which are
Here are the reference resources: