(Revision B3)
page 307 (middle): “…avoid immutability by default…” → “…avoids mutability by default…” (two typos)
(end of the same sentence): “… program.s” → “… programs.”
(bottom of page): “…focus on particular type…” → “…a particular type…”
page 314 (first para): misspelled “concatenate”
page 315 (last para): “…themselves, that we wanted…” → delete “that”
page 324 (lower half): “…our new metric aware…” → “…metrics-aware…”
(last para): “inData.Text.IO.” → missing space
page 329 (middle): “…generate summary statics…” → “statistics”
page 330 (middle): “…we seen observable delay…” → “…see observable delay…”
page 333 (first para): “…problems in like space leaks…” → “…problems like…” (drop “in”)
page 335 (middle): “…doesn’t change typically have…” → “…doesn’t typically have…”