EventFd::defuse does not do what its documentation says

[blp]

EventFd::defuse is implemented and documented as follows:

    /// Defuses `self`, a following call to `poll`, `select` or `epoll` will block.
    /// 
    /// [`EventFd::write`] with `0`.
    pub fn defuse(&self) -> Result<usize> {
        self.write(0)
    }

However, writing to an eventfd adds the number written to a counter maintained in the event, so zero does not have any effect. To achieve the documented effect of causing the next call to block (for POLLIN, presumably), defuse should be implemented as self.read().

[SteveLauC]

Yeah, thanks for reporting, this was reported before in #2422 and has been fixed