operationId and operationIdGenerator in 3.x

[bastia...@instana.com]

Hi folks,

It seems the concepts operationId and operationIdGenerator have been removed completely in 3.x in this commit 

https://github.com/mongodb/node-mongodb-native/commit/086ffb5cf7728e30e9dd15ee9d7156abd2968d43#diff-20ede56fd379a8d037f0c2ef77df1b20

The corresponding test has been disabled in this commit:

https://github.com/mongodb/node-mongodb-native/commit/c18a261b83d2fbf76a3fc83af750dc36abad2755

(and remained disabled forever since: https://github.com/mongodb/node-mongodb-native/blob/master/test/functional/apm_tests.js#L301)

So from looking at the code I guess that specifying an operationIdGenerator does no longer work and that events will never have the operationId property - this also seems to be confirmed by tests with the latest 3.1.4. 

However, the latest 3.1 docs still reference these concepts as if they were a thing: http://mongodb.github.io/node-mongodb-native/3.1/reference/management/apm/

Furthermore (and this is the real issue for us as an APM vendor), there seem to be no docs around how to replace/migrate existing usage of operationId and operationIdGenerator, that is, how to correlate individual commands into a single logical command execution (for example bulk writes).

Kind regards

  Bastian