lwIP 2.1.0 Lightweight IP stack

Modules
Sequential-style APIs
APIs

## Modules
| Netconn API
| NETIF API

## Detailed Description

Sequential-style APIs, blocking functions. More overhead, but can be called from any thread except TCPIP thread. The sequential API provides a way for ordinary, sequential, programs to use the lwIP stack. It is quite similar to the BSD socket API. The model of execution is based on the blocking open-read-write-close paradigm. Since the TCP/IP stack is event based by nature, the TCP/IP code and the application program must reside in different execution contexts (threads).