bulkindexer: get insights into how many docs are pending to be flushed

[Dieterbe]

I want to track how many items are pending to be flushed. should be doable but with a simple len() on the channel, except that it's a private property, so it needs a wrapper function

[mattbaird]

can you submit a PR?

[mattbaird]

also, don't you want the value of docCt in bulk.go? or would you rather have the len of bulkChannel?

[Dieterbe]

i'm not sure TBH. i was looking at the code and couldn't figure out how it works.