First set of commits for realtime support

src/gtfs/realtime.rs

@@ -0,0 +1,36 @@
+/***
+ * Implementation of GTFS-R polling 
+  */
+
+use std::{str::FromStr, time::Duration};
+
+use reqwest::{blocking::Client, header::{HeaderName, HeaderValue}};
+
+use crate::gtfs::structs::{Arrival, Error, Gtfs};
+
+impl Gtfs<'_> {
+    fn realtime_update (&self, arrivals: Vec<Arrival<'_>>) -> Result<bool, Error>{
+
+        // Poll GTFS-R API
+        let client = Client::builder()
+            .timeout(Duration::from_secs(10))
+            .connect_timeout(Duration::from_secs(5))
+            .build()?;
+        
+        let mut response = client
+            .get(self.preferences.realtime_url)
+            .header("x-api-key", self.preferences.realtime_api_key)
+            .send()?;
+
+        // Parse response
+        let response = json::rdr 
+
+        // Match deltas to existing arrivals
+
+        // Update the arrival times       
+
+    }
+
+
+
+}