Macro user_agent_to_external 

macro_rules! user_agent_to_external {
    () => { ... };
}

Make all of lexe_api_core available under [lexe_api].

NOTE: Any crates which can depend on lexe_api_core directly (without lexe-api) should do so to avoid [lexe_api] dependencies. Build the user agent string used for requests to external services at compile time.

Example: “lexe-node/0.6.20”.