IsErrInvalidFixedLength checks if the `err` is of ErrInvalidFixedLength type.

NewFixedLengthFileFormat creates a FileFormat for 'fixedlength2'.

NewReader creates an FormatReader for fixed-length file format.

ColumnDecl describes a column of an envelope.

EnvelopeDecl describes an envelope of a fixed-length input.

FileDecl describes fixed-length schema `file_declaration` setting.

ErrInvalidFixedLength indicates the fixed-length content is corrupted or IO failure.