anchor.diff:  
     /// Return the Streamy implementation type of this entity.
     Type get streamyType;
  -  
  +
     /// Check for deep equality of entities (slow).
     /// TODO(arick): figure out a way to clean this up a bit.
     static bool deepEquals(Entity first, Entity second) {
  
positive.code:     }
      return true;
    }
    
    /// Compute the deep hash code of an entity (slow).
    static int deepHashCode(Entity entity) {
      // Running total, kept under MAX_HASHCODE.
  
negative.code: 
    /// Determine whether this entity has a given field.
    bool containsKey(String key);
  
    /// Deprecated contains() method. Use [containsKey] instead.
    @deprecated
    bool contains(String key) => containsKey(key);
  