Add allow_ingest_behind ffi call for DB Options

src/db_options.rs

@@ -3056,6 +3056,25 @@ impl Options {
             ffi::rocksdb_options_set_blob_compaction_readahead_size(self.inner, val);
         }
     }
+
+    /// Set this option to true during creation of database if you want
+    /// to be able to ingest behind (call IngestExternalFile() skipping keys
+    /// that already exist, rather than overwriting matching keys).
+    /// Setting this option to true has the following effects:
+    /// 1) Disable some internal optimizations around SST file compression.
+    /// 2) Reserve the last level for ingested files only.
+    /// 3) Compaction will not include any file from the last level.
+    /// Note that only Universal Compaction supports allow_ingest_behind.
+    /// `num_levels` should be >= 3 if this option is turned on.
+    ///
+    /// DEFAULT: false
+    /// Immutable.
+    pub fn set_allow_ingest_behind(&mut self, val: bool) {
+        unsafe {
+            ffi::rocksdb_options_set_allow_ingest_behind(self.inner, c_uchar::from(val));
+        }
+    }
+
 }
 
 impl Default for Options {