Fix determination of when to use BinaryRow. Fixes #1018

The code previously tried to infer the type of row based on its contents; it now bases the decision on whether a prepared statement was executed.

Author: bgrainger

src/MySqlConnector/Core/ResultSet.cs

@@ -275,75 +275,7 @@ public async Task<bool> ReadAsync(IOBehavior ioBehavior, CancellationToken cance
 					}
 				}
 
-				if (row is null)
-				{
-					bool isBinaryRow = false;
-					if (payload.HeaderByte == 0 && !resultSet.Connection.IgnorePrepare)
-					{
-						// this might be a binary row, but it might also be a text row whose first column is zero bytes long; try reading
-						// the row as a series of length-encoded values (the text format) to see if this might plausibly be a text row
-						var isTextRow = false;
-						var reader = new ByteArrayReader(payload.Span);
-						var columnCount = 0;
-						while (reader.BytesRemaining > 0)
-						{
-							int length;
-							var firstByte = reader.ReadByte();
-							if (firstByte == 0xFB)
-							{
-								// NULL
-								length = 0;
-							}
-							else if (firstByte == 0xFC)
-							{
-								// two-byte length-encoded integer
-								if (reader.BytesRemaining < 2)
-									break;
-								length = unchecked((int) reader.ReadFixedLengthUInt32(2));
-							}
-							else if (firstByte == 0xFD)
-							{
-								// three-byte length-encoded integer
-								if (reader.BytesRemaining < 3)
-									break;
-								length = unchecked((int) reader.ReadFixedLengthUInt32(3));
-							}
-							else if (firstByte == 0xFE)
-							{
-								// eight-byte length-encoded integer
-								if (reader.BytesRemaining < 8)
-									break;
-								length = checked((int) reader.ReadFixedLengthUInt64(8));
-							}
-							else if (firstByte == 0xFF)
-							{
-								// invalid length prefix
-								break;
-							}
-							else
-							{
-								// single-byte length
-								length = firstByte;
-							}
-
-							if (reader.BytesRemaining < length)
-								break;
-							reader.Offset += length;
-							columnCount++;
-
-							if (columnCount == resultSet.ColumnDefinitions!.Length)
-							{
-								// if we used up all the bytes reading exactly 'ColumnDefinitions' length-encoded columns, then assume this is a text row
-								if (reader.BytesRemaining == 0)
-									isTextRow = true;
-								break;
-							}
-						}
-
-						isBinaryRow = !isTextRow;
-					}
-					row = isBinaryRow ? (Row) new BinaryRow(resultSet) : new TextRow(resultSet);
-				}
+				row ??= resultSet.Command.TryGetPreparedStatements() is null ? new TextRow(resultSet) : new BinaryRow(resultSet);
 				row.SetData(payload.Memory);
 				resultSet.m_hasRows = true;
 				resultSet.BufferState = ResultSetState.ReadingRows;