I was worried about whether I used the right preposition in post Does bridge actually refer to the part on which pedestrians and vehicles move on in everyday English?. So, I googled it. And then I found this example
I shall be coming to see you via the bridge over the railway, not by the road along the river.
I am aware of the usage of the preposition in that sentence. The question is the tense.
If someone said "I am coming to see you ...", I understand they are being on the way come to see me, but how about shall be coming?
Could someone please help make up the context where the expression "I shall be coming to see you ..." would be used?