Returns statistics about the unspent transaction output set.
Note this call may take some time.

{                               (json object)
  "height" : n,                 (numeric) The current block height (index)
  "bestblock" : "hex",          (string) The hash of the block at the tip of the chain
  "transactions" : n,           (numeric) The number of transactions with unspent outputs
  "txouts" : n,                 (numeric) The number of unspent transaction outputs
  "bogosize" : n,               (numeric) A meaningless metric for UTXO set size
  "hash_serialized" : "hex",    (string) The serialized hash
  "disk_size" : n,              (numeric) The estimated size of the chainstate on disk
  "total_amount" : n,           (numeric) The total amount

> bitcoin-cli gettxoutsetinfo 
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "gettxoutsetinfo", "params": []}' -H 'content-type: text/plain;'