What is the burden of proving prejudice against a defendant asserting a right to speedy trial under the California State Constitution?

2. In many cases, state constitutional provisions have been interpreted to afford greater rights to criminal defendants than their federal counterparts. (See People v. Fields (1996) 13 Cal.4th 289, 298.) Sometimes, as here, the procedural burden of asserting a state constitutional right is more onerous than that placed on a defendant asserting a comparable federal right. (See Serna v. Superior Court (1985) 40 Cal.3d 239, 249-250 [state speedy trial provision placed initial burden of demonstrating prejudice on defendant; prejudice was presumed under Sixth Amendment].)