Function createBoundedReader

createBoundedReader(reader: Reader, length: number, context: string): Reader
Creates a bounded Reader from a subset of another Reader's data This prevents reading beyond the specified length
Parameters
- reader: Reader
  The source Reader
- length: number
  Number of bytes to read
- context: string
  Descriptive context for error messages
Returns Reader
A new Reader containing exactly 'length' bytes

Throws
Error if insufficient bytes available