Correct task awaiting with ConfigureAwait(false) in Producer. (#967)

* PersistenceStatus not set correctly (#806)

* use IConsumer/IProducer (#878)

* add native methods from alpine-librdkafka.so (#883)

* correct task awaiting with ConfigureAwait(false).

also added ConfigureAwaitChecker.Analyzer package so you will have warnings in future

* revert unnecessary whitespace changes

* removed dependency

Author: levdimov

src/Confluent.Kafka/Producer.cs

@@ -627,7 +627,7 @@ public async Task<DeliveryResult<TKey, TValue>> ProduceAsync(
             {
                 keyBytes = (keySerializer != null)
                     ? keySerializer.Serialize(message.Key, new SerializationContext(MessageComponentType.Key, topicPartition.Topic))
-                    : await asyncKeySerializer.SerializeAsync(message.Key, new SerializationContext(MessageComponentType.Key, topicPartition.Topic));
+                    : await asyncKeySerializer.SerializeAsync(message.Key, new SerializationContext(MessageComponentType.Key, topicPartition.Topic)).ConfigureAwait(false);
             }
             catch (Exception ex)
             {
@@ -646,7 +646,7 @@ public async Task<DeliveryResult<TKey, TValue>> ProduceAsync(
             {
                 valBytes = (valueSerializer != null)
                     ? valueSerializer.Serialize(message.Value, new SerializationContext(MessageComponentType.Value, topicPartition.Topic))
-                    : await asyncValueSerializer.SerializeAsync(message.Value, new SerializationContext(MessageComponentType.Value, topicPartition.Topic));
+                    : await asyncValueSerializer.SerializeAsync(message.Value, new SerializationContext(MessageComponentType.Value, topicPartition.Topic)).ConfigureAwait(false);
             }
             catch (Exception ex)
             {
@@ -676,7 +676,7 @@ public async Task<DeliveryResult<TKey, TValue>> ProduceAsync(
                         message.Timestamp, topicPartition.Partition, message.Headers,
                         handler);
 
-                    return await handler.Task;
+                    return await handler.Task.ConfigureAwait(false);
                 }
                 else
                 {