Check if node is running

[jbesraa]

It would be useful to expose a function to check if the node is running (ie node.start() ) was invoked.

A possible solution:

/// Check if node runtime is up
pub fn is_node_running(&self) -> bool {
    if self.runtime.read().unwrap().is_some() {
          true
     }
    else { false }
}

[tnull]

Yeah, makes sense to me. Feel free to open a corresponding PR, otherwise I'll make sure to include it in the next release. FWIW, I think I'd prefer the method name to be just is_running