The reactor model is a foundational programming model for distributed computing,
whose focus is modularizing and composing computations and message protocols.
Previous work on reactors dealt mainly with
the programming model and its composability properties,
but did not show how to schedule computations in reactor-based programs.

In this paper, we propose a pluggable scheduling algorithm for the reactor model.
The algorithm is customizable with user-defined scheduling policies.
We define and prove safety and progress properties.
We compare our implementation against the Akka actor framework,
and show up to $3\times$ performance improvements
on standard actor benchmarks.