Combine error information to figure out what transformation is being applied for the current endpoint
rxErrTypeCombine(oldErrType, newErrType)
Arguments
oldErrType: This is the old transformation, by default is zero representing no prior transformation. This parameter is first to allow piping. When the parameter addTransform is missing and oldErrType is a character value, this functions swaps oldErrType and addTransform and assigns oldErrType to zero assuming that there is no prior distribution.
newErrType: This is the new distribution that is being "added" to the current transformation. These assumes the inputs are in the preferred distribution name, as determined by rxPreferredDistributionName()