rest-assured/src/main/java/io/restassured/builder/MultiPartSpecBuilder.java
public MultiPartSpecBuilder controlName(String controlName) {
        Validate.notEmpty(controlName, "Control name cannot be empty");
        this.controlName = controlName;
        this.isControlNameExplicit = true;
        return this;
    }
public MultiPartSpecBuilder controlName(String controlName) {
        Validate.notEmpty(controlName, "Control name cannot be empty");
        this.controlName = controlName;
        this.isControlNameExplicit = true;
        return this;
    }
Specify the control name of this multi-part.

@param controlName The control name to use. Default is <code>file</code>.
@return An instance of MultiPartSpecBuilder