Function rocksdb_merge

pub unsafe extern "C" fn rocksdb_merge(
    db: *mut rocksdb_t,
    options: *const rocksdb_writeoptions_t,
    key: *const c_char,
    keylen: usize,
    val: *const c_char,
    vallen: usize,
    errptr: *mut *mut c_char,
)