Inject an operation in node and broadcast it. Returns the ID of the operation. The signedOperationContents
should be constructed using contextual RPCs from the latest block and signed by the client. The injection of the operation will apply it on the current mempool context. This context may change at each operation injection or operation reception from peers. By default, the RPC will wait for the operation to be (pre-)validated before returning. However, if ?async is true, the function returns immediately. The optional ?chain parameter can be used to specify whether to inject on the test chain or the main chain.
^([a-zA-Z0-9][a-zA-Z0-9])*$