code: void registerMutationCall(@NotNull ApolloMutationCall apolloMutationCall) {
      checkNotNull(apolloMutationCall, "apolloMutationCall == null");
      OperationName operationName = apolloMutationCall.operation().name();
      registerCall(activeMutationCalls, operationName, apolloMutationCall);
    }
docs: <p>Adds provided {@link ApolloMutationCall} that is currently in progress.</p>
  
  <p><b>Note</b>: This method needs to be called right before an apolloCall is executed.</p>