More work on SeqBackgroundService, next step is tests for it.

Core/Logging/SeqHttpClient.cs

@@ -0,0 +1,29 @@
+
+namespace Core.Logging
+{
+    public class SeqHttpClient
+    {
+        HttpClient _httpClient;
+
+        public SeqHttpClient(SeqConfiguration seqConfiguration, HttpMessageHandler httpMessageHandler)
+        {
+            _httpClient = new HttpClient(httpMessageHandler)
+            {
+                BaseAddress = new Uri(seqConfiguration.IngestionEndpoint),
+                Timeout = TimeSpan.FromSeconds(30)
+            };
+
+            _httpClient.DefaultRequestHeaders.Accept.Clear();
+            _httpClient.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
+            if (seqConfiguration.ApiKey != null)
+                _httpClient.DefaultRequestHeaders.Add("X-Seq-ApiKey", seqConfiguration.ApiKey);
+        }
+
+        public SeqHttpClient(SeqConfiguration seqConfiguration) : this(seqConfiguration, new HttpClientHandler()) { }
+
+        public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage httpRequestMessage, CancellationToken cancellationToken)
+        {
+            return await _httpClient.SendAsync(httpRequestMessage, cancellationToken);
+        }
+    }
+}