Thanks for the great answer!

I am looking for the most performant solution.  If I choose the SDK method of writing the data will that then have to read information about the files when I register?  Or is the SDK that writes keeping track of the metadata it needs when the files are committed?   Ie. I don't want to have to treat the files like they are generic files on an S3 and then register them.  With Iceberg the file appender I use to write keeps track of the metadata I need to actually register with, so I don't need to open the files to register them.

If I use the connect I assume that's handled.  Which is the faster option?   I wish to potentially be able to write out several files for a given table at the same time (if I have a lot of insert data) and then register those files together.   I find I can almost tripple performance if I have the right kind of target file system with Iceberg when I do this (basically perform intra-table parallelism on write).