code,message,sender,parameter_1,parameter_2,parameter_3,parameter_4
100,VERSION_SUPPORTED,executor,version,,,
101,WAITING_FOR_VERSION,executor,,,,
102,VERSION_ACCEPTED,streamlet,version,,,
103,RELATION_START,executor,name,,,
104,INPUT_ATTRIBUTE_METADATA,executor,name,type,,
105,OUTPUT_ATTRIBUTE_ALIAS,executor,name,,,
106,OPTION,executor,name,type,value,
107,COMPLETION_REQUEST,executor,what,value,,
108,COMPLETION,streamlet,value,,,
109,COMPLETION_END,streamlet,,,,
110,WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA,executor,,,,
111,OUTPUT_ATTRIBUTE_METADATA,streamlet,name,type,,
112,WAITING_FOR_INPUT_ATTRIBUTES,streamlet,,,,
113,INPUT_ATTRIBUTE,executor,index,value,isNull,
114,WAITING_FOR_OUTPUT_ATTRIBUTES,executor,,,,
115,OUTPUT_ATTRIBUTE,streamlet,value,isNull,,
116,EXECUTOR_ERROR,executor,code,message,,
117,STREAMLET_ERROR,streamlet,code,message,,
118,STREAMLET_WARNING,streamlet,code,message,,
120,RELATION_END,executor,,,,
0,any_streamlet,streamlet,,,,
0,any_executor,executor,,,,