Do not allow writing events after fluent.Close()

[fujimotos]

This implements proposal #104 by Albin Kerouanton.

The behavior of Fluent.PostWithTime() is a bit odd in sync mode;
It will silently reopen connections, even if the client has been
finalized via Fluent.Close().

Change the behavior so that PostWithTime() returns an error
instead of doing an implicit reconnection in such a case.

Signed-off-by: Fujimoto Seiji [email protected]

[fujimotos]

So I spent some time this weekend trying to implement #104:

• Fluent now rejects any event submission after Close().
• chanClosed is renamed to closed for brevity.

I also added a unit test based on the sample code in the original proposal.
(I slightly modified the code so that we can make use of assert.Equal)

@akerouanton Can you check out this PR and see if it is implemented as expected?

[fujimotos]

TODO: Merge this patch along with #107.

[akerouanton]

@fujimotos @tagomoris Let me know when this PR and #107 are merged and a new tag is released. I opened a PR to revendor v1.7.0 into docker. It's still opened, as there're some ongoing discussions that needs to be resolved first, but in any case, I'm willing to do the needed work to revendor when needed. If you're ok with that, just ping me when needed 😉

[fujimotos]

@akerouanton FYI, v1.8.0 was out yesterday.

[akerouanton]

I'll update my PR on docker today 😉