1. A computer-implemented method for highly concurrent processing, comprising: a computing device performing the steps of: accessing a dependency data structure comprising: a plurality of components, each component representing a respective code unit that is executable by a computing system, an explicit pseudo component representing a dependency to be satisfied by an external processing system, and a plurality of dependency arcs connecting the components and the explicit pseudo component, each dependency arc representing a dependency to be satisfied in order to execute a corresponding component in the dependency data structure, including dependency arcs from the explicit pseudo component to a set of two or more of the components; updating the dependency data structure in response to one or more of determining that a component has been executed by the component system, and determining that the explicit pseudo component has been satisfied by the external processing system; identifying components in the dependency data structure that are available to be executed based on the updated dependency data structure, wherein the two or more components are identified as available to be executed in response to updating the dependency data structure to indicate that the explicit pseudo component has been satisfied by the external processing system; and executing the identified components concurrently.