It should be noted that BoltDB has been retired as it suffered from a number of congenital defects. It was implicated in the major Roblox outage that happened a couple months ago, and Consul doesn't use it anymore.
BoltDB author here. Just to clarify, the project was retired because of maintenance burden. CoreOS wanted to make some changes but I didn't have the bandwidth to test and maintain it all. Since this was before Go had good version management, we decided that they could fork the project as "bbolt" and users could move over as needed. They did a good job maintaining it so I eventually archived the original project.
https://news.ycombinator.com/item?id=30015913
(This comment is not to suggest that the Litestream project is of poor quality or anything like that.)