"An abstract class that represents the code and data associated with a single task."
"A subject that broadcasts elements to downstream subscribers."
"A subject that wraps a single value and publishes a new element whenever the value changes."
"A publisher that exposes a method for outside callers to publish elements."
"A protocol that declares a type that can receive input from a publisher."
"A publisher that eventually produces a single value and then finishes or fails."
"A publisher that emits an output to each subscriber just once, and then finishes."
"Customize and receive events from asynchronous sources."
"A layer that draws a cubic Bezier spline in its coordinate space."
"Creates a sample buffer with an image buffer and a callback to make the data ready for use."
"A value that controls the cropping and enlargement of images captured by the device."
"An object that contains graphics functions and configuration state to use in a render command."