retrieve API usage limits; rename Statistics() to GetUserStatistics();

PocketSharp/PocketClient.cs

@@ -22,6 +22,11 @@ namespace PocketSharp
     /// </summary>
     protected readonly HttpClient _restClient;
 
+    /// <summary>
+    /// Caches HTTP headers from last response
+    /// </summary>
+    private HttpResponseHeaders lastHeaders;
+
     /// <summary>
     /// The base URL for the Pocket API
     /// </summary>
@@ -54,6 +59,7 @@ namespace PocketSharp
     public string AccessCode { get; set; }
 
 
+
     /// <summary>
     /// Initializes a new instance of the <see cref="PocketClient"/> class.
     /// </summary>
@@ -144,6 +150,9 @@ namespace PocketSharp
       // validate HTTP response
       ValidateResponse(response);
 
+      // cache headers
+      lastHeaders = response.Headers;
+
       // read response
       var responseString = await response.Content.ReadAsStringAsync();
 
@@ -267,6 +276,11 @@ namespace PocketSharp
     {
       string result = null;
 
+      if (headers == null || String.IsNullOrEmpty(key))
+      {
+        return null;
+      }
+
       foreach (var header in headers)
       {
         if (header.Key == key)
@@ -275,6 +289,7 @@ namespace PocketSharp
           headerEnumerator.MoveNext();
 
           result = headerEnumerator.Current;
+          break;
         }
       }