FLOW

Summary from the TLDR Dev newsletter

Flow is FoundationDB's custom language extension for C++. It adds efficient actor-based concurrency using asynchronous primitives like Future, Promise, wait(), and ACTOR, while compiling down to native C++ for high performance and deterministic simulation. Flow lets developers write distributed asynchronous systems in a much simpler style than callback-heavy C++, with additional constructs like streams (FutureStream/PromiseStream) and choose/when for coordinating concurrent events.