Don't crash if a rate limit header is unparsable

src/Discord.Net.Rest/Net/RateLimitInfo.cs

@@ -15,14 +15,18 @@ namespace Discord.Net
         internal RateLimitInfo(Dictionary<string, string> headers)
         {
             string temp;
-            IsGlobal = headers.TryGetValue("X-RateLimit-Global", out temp) ? bool.Parse(temp) : false;
-            Limit = headers.TryGetValue("X-RateLimit-Limit", out temp) ? int.Parse(temp) : (int?)null;
-            Remaining = headers.TryGetValue("X-RateLimit-Remaining", out temp) ? int.Parse(temp) : (int?)null;
-            Reset = headers.TryGetValue("X-RateLimit-Reset", out temp) ? 
-                DateTimeUtils.FromUnixSeconds(int.Parse(temp)) : (DateTimeOffset?)null;
-            RetryAfter = headers.TryGetValue("Retry-After", out temp) ? int.Parse(temp) : (int?)null;
-            Lag = headers.TryGetValue("Date", out temp) ? 
-                DateTimeOffset.UtcNow - DateTimeOffset.Parse(temp) : (TimeSpan?)null;
+            IsGlobal = headers.TryGetValue("X-RateLimit-Global", out temp) &&
+                bool.TryParse(temp, out var isGlobal) ? isGlobal : false;
+            Limit = headers.TryGetValue("X-RateLimit-Limit", out temp) && 
+                int.TryParse(temp, out var limit) ? limit : (int?)null;
+            Remaining = headers.TryGetValue("X-RateLimit-Remaining", out temp) && 
+                int.TryParse(temp, out var remaining) ? remaining : (int?)null;
+            Reset = headers.TryGetValue("X-RateLimit-Reset", out temp) && 
+                int.TryParse(temp, out var reset) ? DateTimeUtils.FromUnixSeconds(reset) : (DateTimeOffset?)null;
+            RetryAfter = headers.TryGetValue("Retry-After", out temp) &&
+                int.TryParse(temp, out var retryAfter) ? retryAfter : (int?)null;
+            Lag = headers.TryGetValue("Date", out temp) &&
+                DateTimeOffset.TryParse(temp, out var date) ? DateTimeOffset.UtcNow - date : (TimeSpan?)null;
         }
     }
 }