Kraken2: add option for "--use-daemon" with the k2 wrapper #673
Description
Description of feature
Since kraken2 introduced the new wrapper script "k2" there is the option of setting the flag "--use-deamon" ("Spawn a background process that keeps any loaded indexes in memory. Subsequent invokations of classify with this option will skip the index loading process immediately start classifying reads. If a new index is specified that index will also be persisted. Use k2 clean --stop-daemon to stop the background process.")
For large databases this is super useful since the majority of a kraken2 job is used for loading the index into memory. I realize this is tricky to implement in nextflow and would likely, if at all, only work when the kraken2 jobs are not run in parallel. Just thought I'd ask.