transferProperties mutates the 'onto' resource so that it has Promise-valued properties for all
the 'props' input/output props. Importantly all these promises are completely unresolved. This
is because we don't want anyone to observe the values of these properties until the rpc call to
registerResource actually returns. This is because the registerResource call may actually
override input values, and we only want people to see the final value.
The result of this call (beyond the stateful changes to 'onto') is the set of Promise resolvers
that will be called post-RPC call. When the registerResource RPC call comes back, the values
that the engine actualy produced will be used to resolve all the unresolved promised placed on
'onto'.
transferProperties mutates the 'onto' resource so that it has Promise-valued properties for all the 'props' input/output props. Importantly all these promises are completely unresolved. This is because we don't want anyone to observe the values of these properties until the rpc call to registerResource actually returns. This is because the registerResource call may actually override input values, and we only want people to see the final value.
The result of this call (beyond the stateful changes to 'onto') is the set of Promise resolvers that will be called post-RPC call. When the registerResource RPC call comes back, the values that the engine actualy produced will be used to resolve all the unresolved promised placed on 'onto'.