Usually you re-use a ClientBootstrap once you set it up and called connect multiple times on it. This way you ensure that the same EventLoops will be shared across all your connections.
HTTPClient is tied to an event loop, so this should be possible.
https://apple.github.io/swift-nio/docs/current/NIO/Classes/ClientBootstrap.html mentions:
HTTPClient
is tied to an event loop, so this should be possible.