We have exactly the same construct in .Net: a solution file which can contain multiple projects. All of the code is in one place, so you're working with a monolith^. Services are separate and dependencies are checked by the compiler/toolchain - so you design as microservices. Finally deployment is up to you - you can deploy as Microservices, or as one big Monolith.
^ Compile times are fast so this isn't an issue like it can be in other languages.
^ Compile times are fast so this isn't an issue like it can be in other languages.