modules/spring-mock-mvc/src/main/java/io/restassured/module/mockmvc/config/RestAssuredMockMvcConfig.java
public RestAssuredMockMvcConfig headerConfig(HeaderConfig headerConfig) {
        notNull(headerConfig, "HeaderConfig");
        return new RestAssuredMockMvcConfig(logConfig, encoderConfig, decoderConfig, sessionConfig,
                objectMapperConfig, jsonConfig, xmlConfig, headerConfig, asyncConfig, multiPartConfig, mockMvcConfig, paramConfig, matcherConfig);
    }
public RestAssuredMockMvcConfig headerConfig(HeaderConfig headerConfig) {
        notNull(headerConfig, "HeaderConfig");
        return new RestAssuredMockMvcConfig(logConfig, encoderConfig, decoderConfig, sessionConfig,
                objectMapperConfig, jsonConfig, xmlConfig, headerConfig, asyncConfig, multiPartConfig, mockMvcConfig, paramConfig, matcherConfig);
    }
Set the header config

@param headerConfig The {@link HeaderConfig} to set
@return An updated RestAssuredMockMvcConfig