Operation
data class Operation(val operator: String, val operands: List<PdfObject>, val inlineImage: ByteArray? = null)
One content-stream operation: an operator and its operands.
Inline images (BI … ID … EI) are NOT operand-based — their data is binary and not tokenizable — so they are represented as a single operation with operator "BI" and their entire BI…EI source captured in inlineImage. Re-serialization writes inlineImage back verbatim. Regular operations leave it null.