Add Supplier Exporter sample

spring-cloud-function-samples/function-sample-supplier-exporter/src/main/java/com/example/demo/DemoApplication.java

@@ -0,0 +1,55 @@
+package com.example.demo;
+
+import java.util.function.Function;
+
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.cloud.function.context.FunctionRegistration;
+import org.springframework.cloud.function.context.FunctionType;
+import org.springframework.cloud.function.context.FunctionalSpringApplication;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.support.GenericApplicationContext;
+
+@SpringBootConfiguration(proxyBeanMethods = false)
+public class DemoApplication
+		implements ApplicationContextInitializer<GenericApplicationContext> {
+
+	public static void main(String[] args) {
+		FunctionalSpringApplication.run(DemoApplication.class, args);
+	}
+
+	@Override
+	public void initialize(GenericApplicationContext context) {
+		context.registerBean("foobar", FunctionRegistration.class,
+				() -> new FunctionRegistration<>(new Foobar())
+						.type(FunctionType.from(Foo.class).to(Foo.class)));
+	}
+
+}
+
+class Foo {
+	private String name;
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public Foo(String name) {
+		this.name = name;
+	}
+
+	Foo() {
+	}
+}
+
+class Foobar implements Function<Foo, Foo> {
+
+	@Override
+	public Foo apply(Foo input) {
+		System.err.println("HI: " + input.getName());
+		return new Foo("hi " + input.getName() + "!");
+	}
+}