Improve Ample logging for rejected conditional mutations.

[keith-turner]

Is your feature request related to a problem? Please describe.

In situations where conditional mutations to update the metadata table are rejected this code will log a debug line. The debug line does not offer enough information to determine what operation was rejected. For example if there are concurrent bulk imports and compaction contending to update the same tablet and failing the debug message will show which tablet had contention, but looking at the message there is no way to know if it was the bulk import updates or compaction updates that were rejected. It is possible to detemine this by turning on trace logging for the class, but that is extremely verbose and not suitable for leaving on to investigate an occasional problem.

Describe the solution you'd like

Add a short bit of information to the debug statement that gives some details about the operation. This could be done by adding an overloaded version of this method that includes a short description of the operation like :

void submit(RejectionHandler rejectionHandler, String description);

[keith-turner]

Since the description will only be needed in the rejection case constructing it using a supplier would avoid creating it when its not used.

void submit(RejectionHandler rejectionHandler, Supplier<String> descriptionSupplier);