Minor performance improvements.

Author: ernstc

VisualStudioSolutionSecrets/Commands/PushCommand.cs

@@ -88,10 +88,7 @@ public async Task<int> OnExecute()
 
                         if (isFileOk)
                         {
-                            if (!secrets.ContainsKey(secretFile.ContainerName))
-                            {
-                                secrets.Add(secretFile.ContainerName, new Dictionary<string, string>());
-                            }
+                            secrets.TryAdd(secretFile.ContainerName, new Dictionary<string, string>());
                             secrets[secretFile.ContainerName].Add(secretFile.Name, secretFile.Content);
                         }
                         else

VisualStudioSolutionSecrets/Commands/StatusCommand.cs

@@ -52,7 +52,6 @@ public async Task<int> OnExecute()
 
                     foreach (string solutionFile in solutionFiles)
                     {
-                        SolutionFile solution = new SolutionFile(solutionFile);
                         await GetSolutionStatus(solutionFile);
                     }
                 }

VisualStudioSolutionSecrets/Encryption/Cipher.cs

@@ -74,10 +74,12 @@ public void Init(Stream keyfile)
         private void GenerateEncryptionKey(byte[] data)
         {
             byte[] result;
-
+#if NETCOREAPP3_1
             using var hashAlgorithm = SHA512.Create();
-            
             result = hashAlgorithm.ComputeHash(data);
+#else
+            result = SHA512.HashData(data);
+#endif
             _key = Convert.ToBase64String(result);
 
             AppData.SaveData(APP_DATA_FILENAME, new CipherAppData

VisualStudioSolutionSecrets/Repository/GistRepository.cs

@@ -498,10 +498,7 @@ private async Task CheckAccessToken()
             string? content = null;
             string cacheKey = $"{method} {uri}";
 
-            if (useCache && _requestsCache.ContainsKey(cacheKey))
-            {
-                content = _requestsCache[cacheKey];
-            }
+            _ = useCache && _requestsCache.TryGetValue(cacheKey, out content);
 
             if (content == null)
             {