If you have admin access to the stream, you can monitor your stream statistics in real time.
To demostrate this feature I will use httpie:

http —stream —auth=admin:<ADMIN PASSWORD HERE> STATS http://stream.yourradio.com:8000/

Pay attention to «STATS» http method, it allows you to open as tream to Icecast events.
Example output:

server.admin icemaster@localhost undefined
server.clientConnections 208680 undefined
server.clients 1 undefined
server.connections 208775 undefined
server.fileConnections 49 undefined
server.host localhost undefined
server.listenerConnections 168 undefined
server.listeners 0 undefined
server.location Earth undefined
server.clients 2 undefined
server.connections 208776 undefined
server.statsConnections 6 undefined
server.stats 1 undefined
mount.totalBytesRead /radio 707282168
mount.totalBytesSent /radio 2561809
server.clients 3 undefined
server.connections 208777 undefined
server.clients 4 undefined
server.connections 208778 undefined
server.clients 5 undefined
server.connections 208779 undefined
mount.totalBytesRead /radio 707362061
mount.totalBytesSent /radio 2561809
server.clients 6 undefined
server.connections 208780 undefined
server.clientConnections 208681 undefined
server.clients 5 undefined
server.clients 6 undefined
server.connections 208781 undefined
server.clientConnections 208682 undefined
server.clients 5 undefined
mount.totalBytesRead /radio 707442086
mount.totalBytesSent /radio 2561809
server.clients 4 undefined
server.clients 3 undefined
server.clients 2 undefined
server.clients 3 undefined
server.connections 208782 undefined
server.clientConnections 208683 undefined
mount.connections /radio NaN
mount.listeners /radio 1
server.listeners 1 undefined
server.listenerConnections 169 undefined