GH-456 Fix Azure logging

Added static delegate context which holds target context and is also refreshed with new context on each request

Resolves #456

spring-cloud-function-samples/function-sample-azure/src/main/java/example/UppercaseHandler.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import com.microsoft.azure.functions.ExecutionContext;
+import com.microsoft.azure.functions.HttpMethod;
+import com.microsoft.azure.functions.HttpRequestMessage;
+import com.microsoft.azure.functions.annotation.AuthorizationLevel;
+import com.microsoft.azure.functions.annotation.FunctionName;
+import com.microsoft.azure.functions.annotation.HttpTrigger;
+
+import java.util.Optional;
+
+import org.springframework.cloud.function.adapter.azure.AzureSpringBootRequestHandler;
+
+/**
+ * @author Soby Chacko
+ */
+public class UppercaseHandler extends AzureSpringBootRequestHandler<String, String> {
+
+	@FunctionName("uppercase")
+	public String execute(@HttpTrigger(name = "req", methods = {HttpMethod.GET,
+			HttpMethod.POST}, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> request,
+		ExecutionContext context) {
+		return handleRequest(request.getBody().get(), context);
+	}
+
+}