Function librocksdb_sys::rocksdb_sstfilewriter_merge

pub unsafe extern "C" fn rocksdb_sstfilewriter_merge(
    writer: *mut rocksdb_sstfilewriter_t, 
    key: *const c_char, 
    keylen: usize, 
    val: *const c_char, 
    vallen: usize, 
    errptr: *mut *mut c_char
)