The ServiceBlocks are written in code to build new event-based operators that need to use blocking calls like accessing databases, using sockets to send/receive data, accessing the file system, etc.

To create a new ServiceBlock it must be added to a Library project with Add New.. wizard.

ServiceBlock allows processing message events in a background thread safely.

For more information look at programmers ServiceBlock API documentation. To understand Sequencer base consepts, read also the Introduction page.

For no-code usage of Sequencer see Basic Block and Composite Block.