code: public void setHeader(String name, Object value) {
      verifyType(name, value);
      if (value != null) {
        // Modify header if necessary
        if (!ObjectUtils.nullSafeEquals(value, getHeader(name))) {
          this.modified = true;
          this.headers.put(name, value);
        }
      } else {
        // Remove header if available
        if (this.headers.containsKey(name)) {
          this.modified = true;
          this.headers.remove(name);
        }
      }
    }
docs: Set a header.
  
  @param name Name
  @param value Value