Amqp.Session.OnClose C# (CSharp) Method

        protected override bool OnClose(Error error)
        {
            this.CancelPendingDeliveries(error);

            lock (this.ThisLock)
            {
                if (this.state == State.End)
                {
                    return true;
                }
                else if (this.state == State.BeginSent)
                {
                    this.state = State.EndPipe;
                }
                else if (this.state == State.Opened)
                {
                    this.state = State.EndSent;
                }
                else if (this.state == State.EndReceived)
                {
                    this.state = State.End;
                }
                else
                {
                    throw new AmqpException(ErrorCode.IllegalState,
                        Fx.Format(SRAmqp.AmqpIllegalOperationState, "Close", this.state));
                }

                this.SendEnd();
                return this.state == State.End;
            }
        }