client/src/main/java/io/hoplin/MessageConfiguration.java
/**
   * Add new header
   *
   * @param key   the key value to add
   * @param value the value to add
   * @return
   */
Add new header
@param key   the key value to add
@param value the value to add
@return
Add new header @param key the key value to add @param value the value to add @return
public Object addHeader(final String key, final Object value) {
    Objects.requireNonNull(key, "key can't be null");
    headers.put(key, value);
    return this;
  }
public Object addHeader ( final String key , final Object value ) { Objects . requireNonNull ( key , "key can't be null" ) ; headers . put ( key , value ) ; return this ; }
Add new header
 @param key   the key value to add
 @param value the value to add
 @return
Add new header @param key the key value to add @param value the value to add @return