Ambigous subject requirement for polling

[alcjzk]

• Subject states that poll should be called for any I/O between the client and the server.
• Subject states that poll should be called before any read/write operation, implying the above does not only apply to I/O between the client and the server?
• Subject states that poll does not need to be called for reading the config file.

This leaves slight ambiguity on if poll needs to be called for reading normal files besides the config, e.g. while serving files from the file system.

If yes, Reader can be expanded to function as an async ifstream.

[alcjzk]

Requirement is clarified in eval form