function onSubmit() {
			bDataRequested = true;
			that.oRequestor.getModelInterface().fireDataRequested("/" + sFullResourcePath);
		}
Fetches a missing property while drilling down into the cache. Writes it into the cache and
resolves so that the drill-down can proceed.

@param {sap.ui.model.odata.v4.lib._GroupLock} oGroupLock
  An unlocked lock for the group ID
@param {object} oResource
  The resource in the cache on which the missing property is requested. Usually this is the
  last entity in the property path for which the key predicate is known. This keeps $expand
  as short as possible and it allows checking that the navigation property leading to this
  entity is unchanged (by comparing the key predicate). If there is no entity with a key
  predicate at all, SingleCache uses the cache root as oResource.
@param {string} sResourcePath
  The path of oResource relative to the cache
@param {string} sRequestedPropertyPath
  The path of the requested property relative to oResource; this property is requested from
  the server. For annotations, except client annotations, the annotated property is requested
  from the server.
@returns {Promise<void>|boolean}
  A promise which is resolved without a defined result if the requested property is an
  expected late property, or a <code>boolean</code> value if it is not; it is rejected with
  an error if the GET request failed, or if the key predicate or the ETag has changed. The
  returned <code>boolean</code> value tells if the issue can be safely ignored.

@private