anchor.diff:  * `op` is a mandatory field that contains a string value describing the type of operation. Values for the MongoDB connector are `c` for create (or insert), `u` for update, `d` for delete, and `r` for read (in the case of a initial sync).
   * `after` is an optional field that if present contains the state of the document _after_ the event occurred. MongoDB's oplog entries only contain the full state of a document for _create_ events, so these are the only events that contain an _after_ field.
   * `source` is a mandatory field that conains a structure describing the source metadata for the event, which in the case of MongoDB contains several fields: the logical name, the replica set's name, the namespace of the collection, the MongoDB timestamp (and ordinal of the event within the timestamp) at which the event occurred, the identifier of the MongoDB operation (e.g., the `h` field in the oplog event), and the initial sync flag if the event resulted during an intial sync.
  -* `ts_ms` is optional and if present contains the time (using the system clock in the JVM running the Kafka Connect task) at which the connector processed the event. 
  +* `ts_ms` is optional and if present contains the time (using the system clock in the JVM running the Kafka Connect task) at which the connector processed the event.
   
   And of course, the _schema_ portion of the event message's value contains a schema that decribes tihs envelope structure and the nested fields within it.
   
  
positive.code: 
  [NOTE]
  ====
  All MongoDB connector events are designed to work with https://cwiki.apache.org/confluence/display/KAFKA/Log+Compaction[Kafka log compaction], which allows for the removal of older messages as long as at least the most recent message for every key is kept. This is how Kafka can reclaim storage space while ensuring the topic contains a complete dataset and can be used for reloading key-based state. 
  
  All MongoDB connector events for a uniquely identified document will have exactly the same key, signalling to Kafka that only the latest event be kept. And, a tombstone event informs Kafka that _all_ messages with that same key can be removed.
  ====
  
negative.code: |Default
  |Description
  
  |`max.batch.size`
  |`2048`
  |Positive integer value that specifies the maximum size of the blocking queue into which change events read from the database log are placed before they are written to Kafka. This queue can provide backpressure to the oplog reader when, for example, writes to Kafka are slower or if Kafka is not available. Events that appear in the queue are not included in the offsets periodically recorded by this connector. Defaults to 2048, and should always be larger than the maximum queue size specified in the `max.queue.size` property.
  
  |`max.queue.size`
  |`1024`
  |Positive integer value that specifies the maximum size of each batch of events that should be processed during each iteration of this connector. Defaults to 1024.
  
  |`poll.interval.ms`
  |`1000`
  |Positive integer value that specifies the number of milliseconds the connector should wait during each iteration for new change events to appear. Defaults to 1000 milliseconds, or 1 second.
  
  |`connect.backoff.initial.delay.ms`
  |`1000`
  |Positive integer value that specifies the initial delay when trying to reconnect to a primary after the first failed connection attempt or when no primary is available. Defaults to 1 second (1000 ms).
  
  |`connect.backoff.max.delay.ms`
  |`1000`
  |Positive integer value that specifies the maximum delay when trying to reconnect to a primary after repeated failed connection attempts or when no primary is available. Defaults to 120 seconds (120,000 ms).
  
  |`connect.max.attempts`
  |`16`
  |Positive integer value that specifies the maximum number of failed connection attempts to a replica set primary before an exception occurs and task is aborted. Defaults to 16, which with the defaults for `connect.backoff.initial.delay.ms` and `connect.backoff.max.delay.ms` results in just over 20 minutes of attempts before failing.
  
  |`mongodb.members.auto.discover`
  |`true`
  |Boolean value that specifies whether the addresses in 'mongodb.hosts' are seeds that should be used to discover all members of the cluster or replica set (`true`), or whether the address(es) in `mongodb.hosts` should be used as is (`false`). The default is `true` and should be used in all cases except where MongoDB is link:#mongodb-replicaset[fronted by a proxy].
  
  