rest-assured/src/main/java/io/restassured/config/HttpClientConfig.java
public <T> HttpClientConfig setParam(String parameterName, T parameterValue) {
        notNull(parameterName, "Parameter name");
        final Map<String, Object> newParams = new HashMap<String, Object>(httpClientParams);
        newParams.put(parameterName, parameterValue);
        return new HttpClientConfig(httpClientFactory, newParams, httpMultipartMode, shouldReuseHttpClientInstance, NO_HTTP_CLIENT, true);
    }
public <T> HttpClientConfig setParam(String parameterName, T parameterValue) {
        notNull(parameterName, "Parameter name");
        final Map<String, Object> newParams = new HashMap<String, Object>(httpClientParams);
        newParams.put(parameterName, parameterValue);
        return new HttpClientConfig(httpClientFactory, newParams, httpMultipartMode, shouldReuseHttpClientInstance, NO_HTTP_CLIENT, true);
    }
Set a http client parameter.

@param parameterName  The name of the parameter
@param parameterValue The value of the parameter (may be null)
@param <T>            The parameter type
@return An updated HttpClientConfig