impl Send for rate limiter (#150)

src/rocksdb_options.rs

@@ -153,6 +153,9 @@ pub struct RateLimiter {
     inner: *mut DBRateLimiter,
 }
 
+unsafe impl Send for RateLimiter { }
+unsafe impl Sync for RateLimiter { }
+
 impl RateLimiter {
     pub fn new(rate_bytes_per_sec: i64, refill_period_us: i64, fairness: i32) -> RateLimiter {
         let limiter = unsafe {

tests/test_rate_limiter.rs

@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::thread;
 use rocksdb::RateLimiter;
 
 #[test]
@@ -37,3 +38,14 @@ fn test_rate_limiter() {
 
     assert_eq!(rate_limiter.get_total_bytes_through(total), 3072 * 1024);
 }
+
+#[test]
+fn test_rate_limiter_sendable() {
+    let mut rate_limiter = RateLimiter::new(10 * 1024 * 1024, 100 * 1000, 10);
+
+    let handle = thread::spawn(move || {
+        rate_limiter.request(1024, 0);
+    });
+
+    handle.join();
+}