sl@0: ## message with a 'name' header field and unknown 'unkn' field
sl@0: 
sl@0: ## VALID_HEADER includes a LENGTH Header and LENGTH Body
sl@0: VALID_HEADER method_call
sl@0: REQUIRED_FIELDS
sl@0: 
sl@0: HEADER_FIELD UNKNOWN
sl@0: TYPE DICT
sl@0: LENGTH Dict
sl@0: START_LENGTH Dict
sl@0: STRING 'int32'
sl@0: TYPE INT32
sl@0: INT32 0x12345678
sl@0: END_LENGTH Dict
sl@0: 
sl@0: ALIGN 8
sl@0: END_LENGTH Header
sl@0: START_LENGTH Body
sl@0: END_LENGTH Body