Create a MergeRecord processor. Set Min Records = 1, Max Records = 1,000,000, Min Size = 1 B, Max Size = 64 MB. Feed in a few records. No bins will be created. Once the size of the records has reached 4-8 KB or so, it does create the bin, but very small bins won't be created. It appears to be related to buffered output not being counted in the bin's size.