Refactor topic filter naming.

Source/MQTTnet/MqttTopicFilterBuilder.cs

@@ -0,0 +1,57 @@
+using MQTTnet.Exceptions;
+using MQTTnet.Protocol;
+using System;
+
+namespace MQTTnet
+{
+    [Obsolete("Use MqttTopicFilter instead. It is just a renamed version to align with general namings in this lib.")]
+    public class TopicFilterBuilder : MqttTopicFilterBuilder
+    {
+    }
+
+    public class MqttTopicFilterBuilder
+    {
+        MqttQualityOfServiceLevel _qualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce;
+        string _topic;
+
+        public MqttTopicFilterBuilder WithTopic(string topic)
+        {
+            _topic = topic;
+            return this;
+        }
+
+        public MqttTopicFilterBuilder WithQualityOfServiceLevel(MqttQualityOfServiceLevel qualityOfServiceLevel)
+        {
+            _qualityOfServiceLevel = qualityOfServiceLevel;
+            return this;
+        }
+
+        public MqttTopicFilterBuilder WithAtLeastOnceQoS()
+        {
+            _qualityOfServiceLevel = MqttQualityOfServiceLevel.AtLeastOnce;
+            return this;
+        }
+
+        public MqttTopicFilterBuilder WithAtMostOnceQoS()
+        {
+            _qualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce;
+            return this;
+        }
+
+        public MqttTopicFilterBuilder WithExactlyOnceQoS()
+        {
+            _qualityOfServiceLevel = MqttQualityOfServiceLevel.ExactlyOnce;
+            return this;
+        }
+
+        public MqttTopicFilter Build()
+        {
+            if (string.IsNullOrEmpty(_topic))
+            {
+                throw new MqttProtocolViolationException("Topic is not set.");
+            }
+
+            return new MqttTopicFilter { Topic = _topic, QualityOfServiceLevel = _qualityOfServiceLevel };
+        }
+    }
+}