eturn type, other than void, are String, ByteBuffer,
 byte[], any Java primitive or class equivalent, and anything for which there is an encoder. If the method uses a Java
 primitive as a return value, the implementation must construct the text message to send using the standard Java
 string representation of the Java primitive unless there developer provided encoder for the type configured for this
 endpoint, in which case that encoder must be used. If the method uses a class equivalent of a Java primitive