@Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || !getClass().equals(o.getClass())) return false;

    StreamSpec that = (StreamSpec) o;

    return id.equals(that.id);
  }
Copies this StreamSpec, but applies a new partitionCount.

This method is not static s.t. subclasses can override it.

@param partitionCount  The partitionCount for the returned StreamSpec.
@return                A copy of this StreamSpec with the specified partitionCount.
samza-api/src/main/java/org/apache/samza/system/StreamSpec.java