"dataType" property does not apply to HTTP request body

The "dataType" property in function.json does not apply for HTTP bindings. One could very reasonably expect "dataType" to be applied to the HTTP body (instead of relying on HTTP headers that are either set on the client-side or via proxies / API Management).

Note that confusion also lies in the fact that we need to add information to documentation: https://github.com/MicrosoftDocs/azure-docs/issues/24702

Start by reviewing HTTP binding handling and the function.json dataType property, then trace how the HTTP request body’s type is currently determined from headers. Define the intended behavior and acceptance cases for applying dataType to the body, and consult the linked Azure Docs issue for the documentation impact.

Written by the indexing model from the issue text.