Function run_build_streaming 

pub(crate) fn run_build_streaming<'a, BS, DS, R, SpawnFut>(
    semaphore: &'a Semaphore,
    blob_service: BS,
    directory_service: DS,
    expected_outputs: Vec<String>,
    refscan_needles: Vec<String>,
    spawn: impl FnOnce() -> SpawnFut + Send + 'a,
) -> BoxStream<'a, BuildUpdate>
where
    BS: BlobService + Clone + 'a,
    DS: DirectoryService + Clone + 'a,
    R: SandboxOutputs + Send + Sync + 'static,
    SpawnFut: Future<Output = Result<(BoxStream<'static, SandboxEvent>, R), BuildFailure>> + Send + 'a,

Executes a sandboxed build and streams its progress and outputs.