There is a remarkable amount of memory allocation occurring under load
to perform the field name "app." prefixing by the Beeline with "app.".
This change skips the memory allocations needed for string concat and
usage if the "app." prefix is already present on the field name
provided.

We have concluded that calling functions as parameters to functions is
not as easy to read as local variable assignment and using the variable
as the parameter. Benchmarking indicates that there is no difference in
allocations between assigning a local variable in AddField() and having
a function return a value that is immediately used as a parameter still
within the scope of AddField().

Co-authored-by: JamieDanielson <[email protected]>