The core HTTP components (HttpCore).
These deal with the fundamental things required for using the
HTTP protocol, such as representing a
{@link org.apache.http.HttpMessage message} including it's
{@link org.apache.http.Header headers} and optional
{@link org.apache.http.HttpEntity entity}, and
{@link org.apache.http.HttpConnection connections}
over which messages are sent. In order to prepare messages
before sending or after receiving, there are interceptors for
{@link org.apache.http.HttpRequestInterceptor requests} and
{@link org.apache.http.HttpResponseInterceptor responses}.