Revert "less concurrent connections for more concurrent processes"

This reverts commit dd00c50841ca5e56850f6ed86c4e1aa628729c0f.
Revert "mostly finished rewrite, do not use yet"

This reverts commit 4fa6e6d7e132a8aa0fce7f269c3ca531139c35ab.
default concurrency 48
version bump