Networking TS Facilities provide a framework within which testable, extensible, asynchronous programs can be written in C++. In addition to this, the Networking TS sets out specific “I/O object” types that provide means of performing I/O and thus enable the authoring of such programs to take place immediately. These provided I/O objects will invariably not be sufficient. The talk will explore the task of creating new I/O object types by motivating and illustrating the facilities and patterns provided by the Networking TS for this purpose.