Function zstd_sys::ZSTD_toFlushNow

pub unsafe extern "C" fn ZSTD_toFlushNow(
    cctx: *mut ZSTD_CCtx
) -> usize

ZSTD_toFlushNow() : Tell how many bytes are ready to be flushed immediately. Useful for multithreading scenarios (nbWorkers >= 1). Probe the oldest active job, defined as oldest job not yet entirely flushed, and check its output buffer. @return : amount of data stored in oldest job and ready to be flushed immediately. if @return == 0, it means either :

• there is no active job (could be checked with ZSTD_frameProgression()), or
• oldest job is still actively compressing data, but everything it has produced has also been flushed so far, therefore flush speed is limited by production speed of oldest job irrespective of the speed of concurrent (and newer) jobs.