- An event to create a new CallList (currently a new transaction when tracing a block). 
- An - Evmevent proxied by the Moonbeam runtime to this host function.
evm -> moonbeam_runtime -> host.
 
- A - Gasometerevent proxied by the Moonbeam runtime to this host function.
evm_gasometer -> moonbeam_runtime -> host.
 
- A - Runtimeevent proxied by the Moonbeam runtime to this host function.
evm_runtime -> moonbeam_runtime -> host.
 
- Allow the tracing module in the runtime to know how to filter Step event
content, as cloning the entire data is expensive and most of the time
not necessary.