Prospectus excerpt:  We are offering to the public 10,000,000 of our 6.75% Series C Cumulative Redeemable Preferred Shares of Beneficial Interest, $0.01 par value per share, which we refer to in this prospectus supplement as the Series C Preferred Shares. This is an original issuance of the Series C Preferred Shares. Holders of Series C Preferred Shares will be entitled to receive cumulative cash dividends at a rate of 6.75% per annum of the $25.00 per share liquidation preference (equivalent to $1.6875 per annum per share). Dividends will be payable quarterly in arrears on the 15th day of each March, June, September and December, commencing on December 15, 2021 (provided that if any dividend payment date is not a business day, then the dividend which would otherwise have been payable on that dividend payment date may be paid on the next succeeding business day). Dividends will accumulate and be cumulative from, and including, the date of original issuance, which is expected to be August 24, 2021.