Limiting the number of connections to improve raw performance

By default the library uses a connection pool and re-use connections as needed. It is important to not let the connection pool grow too large as it takes resources in memory. One way consist of setting the maximum number of connection per host or in total:

AsyncHttpClientConfig config = new AsyncHttpClientConfig.Builder()
AsyncHttpClient c = new AsyncHttpClient(config);

There is no magic number, so you will need to try it and decide which one gives the best result.