add method Signatures_Fee()

Lisk.API.csproj

@@ -100,6 +100,7 @@
     <Compile Include="Responses\peers_get_response.cs" />
     <Compile Include="Responses\Peer_Object.cs" />
     <Compile Include="Responses\signatures_add_response.cs" />
+    <Compile Include="Responses\signatures_fee_response.cs" />
     <Compile Include="Responses\signatures_get_response.cs" />
     <Compile Include="Responses\Signature_Object.cs" />
     <Compile Include="Responses\transactions_getListUnconfirmed_response.cs" />

LiskAPI.cs

@@ -532,6 +532,17 @@ public async Task<signatures_add_response> Signatures_Add(string secret, string
             return pr.StartsWith("ERROR") ? new signatures_add_response {error = pr, success = false} : JsonConvert.DeserializeObject<signatures_add_response>(pr);
         }
 
+        /// <summary>
+        /// Get the fee for a signature.
+        /// </summary>
+        /// <returns></returns>
+        public async Task<signatures_fee_response> Signatures_Fee()
+        {
+            const string url = "/api/signatures/fee";
+            var gr = await HttpGetRequestAsync(url, User_Agent);
+            return gr.StartsWith("ERROR") ? new signatures_fee_response { error = gr, success = false } : JsonConvert.DeserializeObject<signatures_fee_response>(gr);
+        }
+
         /// <summary>
         /// Get the total number of registered delegates.
         /// </summary>

Responses/signatures_fee_response.cs

@@ -0,0 +1,10 @@
+using Newtonsoft.Json;
+
+namespace Lisk.API.Responses
+{
+    [JsonObject(MemberSerialization = MemberSerialization.Fields)]
+    public class signatures_fee_response : BaseResponse
+    {
+        public long fee;
+    }
+}