default_seed is used initialize the pseudo-random generator that chooses random values from generators, in each test that is not provided its own seed.

default_sizes determines the default sequence of sizes used in generating values.

default_trial_count determines the number of trials per test, except in tests that explicitly override it.

default_can_generate_trial_count determines the number of trials used in attempts to generate satisfying values, except in tests that explicitly override it.

default_shrink_attempts determines the number of attempts at shrinking when running test or iter with ~shrinker and without ~shrink_attempts