Suppose the following flow:

public IntegrationFlow sendMailFlow() {
        return IntegrationFlow.from(inputChannel())
                .handle("something","someMethod")
                .channel(outputChannel())
                .get();
}

How I do a manually put a message in the input channel?

I would like something like this:

Message<String> message = MessageBuilder.withPayload("Test).build();
Something.submitToChannel("outputChannel", message);

Note: I am calling this from a Web Endpoint.

Thanks