Earlier quoted context omitted.
I'm confused by the decision in DoChan to return a channel (instead of accepting one supplied by the caller) and then, given that, also not to close that channel (is something else going to be sent to the channel in the future?). Both seem like strange/unnecessary design decisions.
Returning a channel avoids questions of what happens if sending to a caller-supplied channel blocks. DoChan returns a channel with a single-element buffer, so a single send to the channel will always succeed without blocking, even if the caller has lost interest in the result and discarded the channel. DoChan doesn't close the channel because there isn't any reason to do so.
However, not closing the channel you specifically chose to control all sending to is just lazy/rude. Even though the caller should receive from the channel once and then forget about it, closing the channel after sending would prevent incorrect subsequent receives from hanging forever.
All this having been said, contributing to these libraries seems better than complaining about them, but I don't know how the golang.org/x stuff is maintained; looks like this one is here: https://github.com/golang/sync