Module that should be used in sources - elements producing data. Declares appropriate behaviours implementation and provides default callbacks implementation.

Behaviours for sources are specified in modules Membrane.Element.Base and Membrane.Element.WithOutputPads.

Source elements can define only output pads. Job of a usual source is to produce some data (read from soundcard, download through HTTP, etc.) and send it through such pad. If the pad works in pull mode, then element is also responsible for receiving demands and send buffers only if they have previously been demanded (for more details, see Membrane.Element.WithOutputPads.handle_demand/5 callback). Sources, like all elements, can of course have multiple pads if needed to provide more complex solutions.