Explain the burst concept in comments for Poloniex

src/poloniex/api.rs

@@ -47,6 +47,7 @@ pub struct PoloniexApi {
     api_key: String,
     api_secret: String,
     http_client: Client,
+    burst: bool,
 }
 
 
@@ -69,15 +70,27 @@ impl PoloniexApi {
                api_key: creds.get("api_key").unwrap_or_default(),
                api_secret: creds.get("api_secret").unwrap_or_default(),
                http_client: Client::with_connector(connector),
+               burst: false,
            })
     }
 
+    /// The number of calls in a given period is limited. In order to avoid a ban we limit
+    /// by default the number of api requests.
+    /// This function sets or removes the limitation.
+    /// Burst false implies no block.
+    /// Burst true implies there is a control over the number of calls allowed to the exchange
+    pub fn set_burst(&mut self, burst: bool) {
+        self.burst = burst
+    }
+
     fn block_or_continue(&self) {
-        let threshold: u64 = 167; // 6 requests/sec = 1/6*1000
-        let offset: u64 = helpers::get_unix_timestamp_ms() as u64 - self.last_request as u64;
-        if offset < threshold {
-            let wait_ms = Duration::from_millis(threshold - offset);
-            thread::sleep(wait_ms);
+        if ! self.burst {
+            let threshold: u64 = 167; // 6 requests/sec = 1/6*1000
+            let offset: u64 = helpers::get_unix_timestamp_ms() as u64 - self.last_request as u64;
+            if offset < threshold {
+                let wait_ms = Duration::from_millis(threshold - offset);
+                thread::sleep(wait_ms);
+            }
         }
     }
 
@@ -787,3 +800,44 @@ impl PoloniexApi {
         self.private_query("toggleAutoRenew", &params)
     }
 }
+
+
+#[cfg(test)]
+mod poloniex_api_tests {
+    use super::*;
+
+    #[test]
+    fn should_block_or_not_block_when_enabled_or_disabled() {
+        let mut api = PoloniexApi {
+            last_request: helpers::get_unix_timestamp_ms(),
+            api_key: "".to_string(),
+            api_secret: "".to_string(),
+            http_client: Client::new(),
+            burst: false,
+        };
+
+        let mut counter = 0;
+        loop {
+            api.set_burst(false);
+            let start = helpers::get_unix_timestamp_ms();
+            api.block_or_continue();
+            api.last_request = helpers::get_unix_timestamp_ms();
+
+            let difference = api.last_request - start;
+            assert!(difference >= 166);
+            assert!(difference < 1000);
+
+
+            api.set_burst(true);
+            let start = helpers::get_unix_timestamp_ms();
+            api.block_or_continue();
+            api.last_request = helpers::get_unix_timestamp_ms();
+
+            let difference = api.last_request - start;
+            assert!(difference < 10);
+
+            counter = counter + 1;
+            if counter >= 3 { break; }
+        }
+    }
+}