Get some metrics about the Opal system status. The following information are returned: `timestamp` (the EPOC time at which the metrics were collected), `uptime` (the running time in millis), `heapMemory` (the memory currently used), `nonHeapMemory` (the memory that can be used), `threads` (the current (count) and maximum (peak) numbers of threads), `gcs` (the garbage collectors activity).
oadmin.system_metrics(opal)Opal connection object.
if (FALSE) {
o <- opal.login('administrator','password', url='https://opal-demo.obiba.org')
oadmin.system_metrics(o)
opal.logout(o)
}