Package plugin provides a gRPC-based plugin system allowing programs to dynamically execute custom code that satisfy the plugin interface. Plugins are external binaries that serve gRPC requests over a UNIX domain socket on the local machine. Each plugin creates a socket using a unique identifier passed as an argument from the host application to the plugin. Plugins make use of the protobuf "Any" type in order to allow user-defined inputs and outputs to keep strong typing across application and language boundaries.