Used on components, this annotation marks the method parameter that will be used
to pass in the message payload. Note that the parameter type will be used to do
any auto conversions using transformers available inside the Mule container. Mule
has a number of standard transformers for dealing with common Java types such as
XML documents, streams, byte arrays, strings, etc. It is also very easy for users
to define their own using the
Transformer
annotation.