review feedback

Author: Wraith2

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParser.cs

@@ -13093,9 +13093,9 @@ bool writeDataSizeToSnapshot
             );
             charsLeft = len;
 
-            // If total length is known up front, the length isn't specified as unknown 
-            // and the caller doesn't pass int.max/2 indicating that it doesn't know the length
-            // allocate the whole buffer in one shot instead of realloc'ing and copying over each time
+            // If total data length is known up front from the plp header by being not SQL_PLP_UNKNOWNLEN
+            //  and the number of chars required is less than int.max/2 allocate the entire buffer now to avoid
+            //  later needing to repeatedly allocate new target buffers and copy data as we discover new data
             if (buff == null && stateObj._longlen != TdsEnums.SQL_PLP_UNKNOWNLEN && stateObj._longlen < (int.MaxValue >> 1))
             {
                 if (supportRentedBuff && stateObj._longlen < 1073741824) // 1 Gib