Function librocksdb_sys::crocksdb_sstfilewriter_merge

pub unsafe extern "C" fn crocksdb_sstfilewriter_merge(
    writer: *mut SstFileWriter, 
    key: *const u8, 
    key_len: size_t, 
    val: *const u8, 
    val_len: size_t, 
    err: *mut *mut c_char
)