Apache Serf

The serf library is a high performance C-based HTTP client library built upon the Apache Portable Runtime (APR) library. It is permissively licensed under the Apache License, v2.

Key features:

• multiplexed, asynchronous connections
• SSL/TLS support
• full HTTP pipelining
• multiple authentication modes (Basic, Digest, Kerberos/NTLM)
• zero-copy support for increased throughput

Serf is the default client library of Apache Subversion